308 load development quandary

[Newts]

Hello all, new guy here. Ran into something I had not seen before when developing a load for a new gun I bought. I started 'googling' for info and kept seeing some explanations to my situation popping up on here. Hate to make my first post so long, but figured I would give as much pertinent information up front as I can.

Here is the info - New gun, Ruger American 22" Barrel.
Powder is IMR4064
Primers are Fed210
Brass is Sig - unfired holds ~54.3gr H2O
Bullets are Nosler 165gr BT's
OAL is 2.825"

When I first got the gun I just put on an old scope I had laying around, just to be able to shoot it while I waited for my new scope to arrive. I ran 5 rounds of factory Hornady Whitetail 150gr through it. Shot great with it.

Then, last weekend, I decided to do some load testing with the above components. I just wanted to run some loads over the chronograph to get a general idea of velocities and look for any pressure issues. I was not looking for groups or anything. I did use a target at 100 yards for an aiming point.

Here are the chronograph results. I uploaded them to my google drive. What you will see is the first shot came from a cleaned/cold barrel. I shot one of the Hornady factory rounds first. Then, starting with 41gr of 4064, I worked up in .5gr increments up to 44.5gr, which is what Nosler listed as their max.

Right off the bat, I saw that I was flatlining quite a bit. I was not sure if my chronograph was just messing around, but the target kinda showed that it might not have been. I still question it a little and am planning to move the chronograph further away next time. Here is a picture of the target.

When I did not see much in the way of pressure signs, I loaded up a 45gr round. It was shot #10. At this point, I did not see any blaring overpressure signs, and I saw that the shot fit right in with the others, so I decided to load up 3 just for a quick look at how they might group.

Those 3 are in the lower left-hand corner of the target. Shot #11-#13.

I was somewhat apprehensive about going over the max charge listed by Nosler, but at the same time knew I was not over max based on data from Hodgdon. I also knew my case volume was more than Nosler and my OAL was greater, which made sense that pressures should be a tad lower.

But being apprehensive, I was really trying to look for any signs. This is where I am not sure if my mind was playing tricks on me or not. I want to say the bolt lift was a little heavier after that first shot, of the 3, and the same after the second. But I cannot be absolute. I know it was not really bad. What I mean is it did not take much more force to lift the bolt, a little I think, and nothing more noticeable to actually extract the case.

I did go ahead and stop there. I did not feel comfortable, and I did not see any point of trying groups without having the new scope on. There is a 'little' more to the story, but I do not want to drag out my first post that long.

My quandary is the velocity readings I was getting. I have never seen a velocity flat line for 2 full grains. Just looking for extra eyes on the situation. Thanks.

[kilotanker22]

I have had a velocity flat spot that was 2 grains wide. With my 270 wsm, 22 inch barrel. from 70.5-72.5 grains of H-1000I literally get the same average velocity.... However, I get the best groups at 70.5 grains h-1000, also the extreme spread and standard deviation are much lower at the lower charge weight.

I assumed the reason for this was the short barrel was only able to burn so much of the slow powder I was using. I don't know for sure.

What I would do is load some sets of 5 rounds. Starting at the beginning of your flat spot and increasing each 5 round set by .2 grain increments. Shoot each of the 5 round sets over the chronograph and focus on shooting as well as you can for groups. Record average velocity, extreme spread and standard deviation. I would be willing to bet that one of those loads will not only shoot better, but the velocity numbers will be better than the others as well. That should give you a better idea of what's really going on.

Personally I have never seen a hard bolt lift that didn't also have other pressure signs prior.

[T. O'Heir]

Accuracy is far more important than velocity.
Hodgdon's current data for a 165(who made it doesn't matter.) is 42.0 to 46.3(C). Differences in test components/conditions will account for the differences between No$ler's data and Hodgdon's. Hodgdon used a 1 in 12 24" barrel for one. No$ler used a 24" 1 in 10 barrel. Vs your 22" barrel. That will give you slightly different velocity
You're fine either way. You don't have to use No$ler data. One loads according to the bullet weight, not who made it. Your case volume doesn't matter much.
Data for a 150 is not going to be the same or apply to a 165. It's an apples and oranges comparison. You have to work up a load for that bullet weight.

[HiBC]

Years ago Serra sent out a newsletter.In one of those they had an article about using what you refer to as "flat lining' as an indicator you have hit the max load wall.

I've used the idea for wildcat load development,etc over the years with IMO,good results.

Back before there was any published data for a 69 gr hpbt match bullet and Varge,I called Nosler and Hogdon about data.Back then,they would send some data by snail mail.

Meanwhile,I used my chrono till I got diminishing returns,powder s velocity.

I forget whch was which,but IIRC (do not use ths data,its from memory,to illustrate my point.Do not trust my memory!)

One quote was 25 gr,one was 25.5 gr,and my "hitting the wall" split that at 25.3.(Once again,don't trust those numbers.They are from memory.)

Myself,I quit adding powder when my velocity increase per 1/2 gr decreases.

I do not keep increasing charge.Seems futile to add more powder for diminishing returns.

I make no claim to being an internal ballistics expert. I just tried Sierras suggestion and it works for me. YMMV


This assumes modern,strong bolt action equivalent rifles. Don't apply it to Krags,Rolling blocks,most lever actions,etc

[Mal H]

I still question it a little and am planning to move the chronograph further away next time.

In order to eliminate the chronograph acting up from this discussion, how close was it to the muzzle for the shots you made?

[Newts]

In order to eliminate the chronograph acting up from this discussion, how close was it to the muzzle for the shots you made?

I typically set it 12'-15'. I shoot at home so I just leave it set up. I'll verify what distance though.

I just saw during my digging that setting it out to 20' or so would not make that much difference and it could eliminate the possibility of errors due to gasses.

[HiBC]

Early/late hours with low sun angles can make for screwy readings on the chrono.

[Newts]

Personally I have never seen a hard bolt lift that didn't also have other pressure signs prior.

This is the other part of the story. I thought that I might have been seeing pressure signs actually, after the fact that is. After I started looking at my brass real close I was seeing some ejector swipes and slight cratering.

However, turns out the ejector swipes are coming from a sharp edge on the ejector, and the primer cratering from the clearance of the firing pin hole. I am pretty convinced that they are not pressure signs.

Here is a picture showing the swipe and cratering.

The one with an unfired primer I stuck into the bolt face and just turned it a little by hand. The one that has been shot is one of the 45grain loads.

Here is a picture showing the bolt face.

I've ran into soft primers and firing pin clearences before in relation to cratering.

[Newts]

Early/late hours with low sun angles can make for screwy readings on the chrono.

When I started seeing the flat line I started watching if there were any shadows over one screen or the other. Each time I'd go look at the target I made a mental note of it. Never had shadows over them.

Testing was done between 2 and 3:30. Beautiful bluebird day. Sky screens on.

[Newts]

Originally Posted by T. O'Heir

Accuracy is far more important than velocity.
Hodgdon's current data for a 165(who made it doesn't matter.) is 42.0 to 46.3(C). Differences in test components/conditions will account for the differences between No$ler's data and Hodgdon's. Hodgdon used a 1 in 12 24" barrel for one. No$ler used a 24" 1 in 10 barrel. Vs your 22" barrel. That will give you slightly different velocity
You're fine either way. You don't have to use No$ler data. One loads according to the bullet weight, not who made it. Your case volume doesn't matter much.
Data for a 150 is not going to be the same or apply to a 165. It's an apples and oranges comparison. You have to work up a load for that bullet weight.

I am not so much concerned with velocity than accuracy, however, if I can have both that would be nice.

The high end 3 shot group gave me under an inch. That was also with a cheap scope that is not at all good for target work.

So it's hard to just turn my nose up at that group. But, safety trumps everything else in my book, so unless I can be sure I am going to be backing down off that higher end load.

[Newts]

Originally Posted by HiBC

Years ago Serra sent out a newsletter.In one of those they had an article about using what you refer to as "flat lining' as an indicator you have hit the max load wall.

I've used the idea for wildcat load development,etc over the years with IMO,good results.

Back before there was any published data for a 69 gr hpbt match bullet and Varge,I called Nosler and Hogdon about data.Back then,they would send some data by snail mail.

Meanwhile,I used my chrono till I got diminishing returns,powder s velocity.

I forget whch was which,but IIRC (do not use ths data,its from memory,to illustrate my point.Do not trust my memory!)

One quote was 25 gr,one was 25.5 gr,and my "hitting the wall" split that at 25.3.(Once again,don't trust those numbers.They are from memory.)

Myself,I quit adding powder when my velocity increase per 1/2 gr decreases.

I do not keep increasing charge.Seems futile to add more powder for diminishing returns.

I make no claim to being an internal ballistics expert. I just tried Sierras suggestion and it works for me. YMMV


This assumes modern,strong bolt action equivalent rifles. Don't apply it to Krags,Rolling blocks,most lever actions,etc

If I had not have loaded up the rounds already I might have just stopped after a few of the ones flatlined. But I was not seeing pressure, so I figured I might just go ahead and shoot them. And once I saw they were all landing in the same area on the target, it was one of those interesting things to me. After the fifth one I shot(#9) I thought something was really wrong with my chronograph. So that's part of the reason I went back and loaded up another one at 45gr. When I saw it jumped up to 2700, I wondered if it was a fluke. So that was part of the reason I decided to test 3 at that level.

What is interesting is how it jumps. First 3 were upper 2400's, then jumps to the mid 2600's for the next 5, then jumps to over 2700 with the next load.

I've seen loads fluctuate, but never like this.


Thanks for all the replies guys.

[Mal H]

Originally Posted by Newts

I typically set it 12'-15'.

That's fine. Just wanted to be sure it was no closer than 10'. No need to move it.

[308Loader]

I had a very similar experience, IMR4064,CCI BR2 primers in a Savage Mod10-T-SR, about the same charge as your test #5-9. Thought I had mislabeled my test loads. Repeated the test and same results. Thought I had lost my mind or broke my equipment. Thanks for the post.

[Unclenick]

I took Hodgdon's data for the Hornady flat base spire point seated to 2.75" COL and matched it in QuickLOAD (QL). I then shortened the barrel in QL to 22" and changed the bullet and the COL. The pressure went up about 2000 psi, due to the long bullet, allowing me to determine that with the Nosler BT at 2.825" COL, 45.8 grains of 4064 would match the pressure of 46.3 grains with the Hornady in the Hodgdon test gun.

In the plot below, the orange line is a theoretical change in velocity with charge weight for the Hodgdon load. The dotted blue line is the trendline for Newts's data. You can see the two are pretty close. The surprising thing about Newts data is the big velocity jump at 42.5 grains. The average is across the span for the Hodgdon data is about 50 fps per grain of powder, but that jump is 200 fps in half a grain or 8 times the average. That's more than random velocity extreme spread is likely to produce on its own. The energy in half a grain of powder is not enough to account for that much difference.

Then the flat spot comes along and makes more sense, relative to the trendline. Indeed, Federal Gold Medal Match with the 168-grain Sierra Match King bullet is loaded with 43.5 grains of IMR 4064 and the 175-grain SMK with 41.7 grains, so for the slightly lighter 165-grain bullet, 44 grains would be an expected match based on weight alone. In fact, that does seem to be about the middle of the flat spot.

It isn't really possible for half a grain to provide enough energy for the 200 fps velocity jump, so something else is going on there. I just don't know what. Chronograph malfunction was my first thought, but the overall velocity trendline looks better than I'd expect with that, so another test for consistency would clarify it. If would be good to get a couple more strings, maybe in 0.3-grain steps to better understand the real variance in the load.

The powder charge fills the case too well for powder position to be the culprit. Primers not properly reconsolidated in the primer pocket would increase variation. A bullet jamming the lands, either because of incomplete seating or because the lot has been made with one contributing set of tooling producing a shorter-than-normal ogive radius could do it. There have been a couple of recent threads where examples of this have come up that, in one instance, moved the bullet jump forward a full 0.020". It's one of the hazards of trying to seat very close to the throat that such a flaw could cause a bullet jam. It is possible something mechanical is contributing, like a bolt lug in need of lapping not completing contact before that point. More data is the most I can suggest at this juncture.

Lastly, I also note a drop between 45.5 and 46.0 grains. That could be a simple random drop, but be aware a drop in velocity with increase in charge weight can be a pressure sign. It can happen because the chamber is stretching. But the variance off the trendline for the string overall is great enough that I am not inclined to jump to that conclusion. Lack of serious perimeter flattening of the primer cups is the other reason.

So, more data. Smaller steps. Carefully seat the primers so they are 0.003" deeper below flush with the head than they are when you feel their feet kiss the bottom of the primer pocket. This usually means seating them pretty hard, but it does reduce velocity variation. The flat spot in this data seems to be in the right place, but the variance is very high.

[44 AMP]

If I read it right, he fired one round with each listed powder charge weight.

One round only tells us what happened when that specific individual round fired.

There are a lot of things that can cause a variance in one single round. Which is why we use groups not single rounds for accuracy and strings not single shots for velocity determinations, taking the average overall, not single highs or lows...

I think you ought to shoot more of them, before deciding what is, and isn't significant, but, that's just me...

Good Luck!

[Newts]

I agree, there are a lot of things that can cause variance in one round, but I tried my best to make sure each one was exactly like other than the powder charge.

I was not looking for accuracy or for specific velocity averages. Just general velocity averages.

I have seen ~20-30fps swings both ways before so the mild up and downs did not mean anything to me. Just the big jumps and the flat lines.

[Newts]

Unclenick, thanks for all the data you posted. I don't have a lot of time to respond but you brought up some points that I can give some more information on. I hope to have more time sometime later today.

One thing I noticed is that you plotted a charge up to 46.5gr for my velocity data? Maybe I am misreading that? I only loaded up to 45-grains. The last 4 velocity readings were that 45gr charge.

So I take it QL did not see a pressure issue with my load at 45gr? I have seen where guys take all the data from a load and input it and get a pressure estimation. I don't know how its done though, so maybe it doesn't work like that? One of these days I have sworn I will get that program. I have heard a lot of good things about it and how useful a tool it is.

[Unclenick]

Newts,

Sorry about that. In Excel I just did a drag of the increments, forgetting you mentioned loading 3 copies for the last three. A corrected plot is below. Also very interesting that shot 10 is so far from the next three 45 grain charges. Looking at the table of times between shots, the thing that stands out is the long delay between 10 and 11. That suggests you have a heat-related issue with the barrel walking. The fact shot 1, 2 and 3 have close to the same windage tends to confirm that you've got horizontal thermal POI shift. The displacement of 10 from 11, 12 and 13 may mean that walk is actually diagonal, and the only reason 1,2 and 3 don't have the same elevation as 11, 12 and 13 may be due to the difference in muzzle position at their longer barrel times and that the vertical component of the heat walking is neutralizing the vertical component of barrel swing in shot 4 through 10. Stranger things have happened.

I would check for stock contact. Slip the usual dollar bill around the barrel and slide it down. Do it again when the barrel is hot. See if you can feel a difference.

Just to be sure, other things to check for are loose stock screws or scope screws — barrel making contact with the stock somewhere.

 Shots     Time Between

 1 to 2       2 min
 2 to 3       3 min
 3 to 4       3 min
 4 to 5       4 min
 5 to 6       6 min
 6 to 7       6 min
 7 to 8       5 min
 8 to 9       6 min
 9 to 10     10 min
10 to 11     22 min
11 to 12      4 min
12 to 13      2 min

Again, to emphasize the importance of primer seating to set the thickness of the bridge of priming mix between the cup and anvil:

"There is some debate about how deeply primers should be seated. I don’t pretend to have all the answers about this, but I have experimented with seating primers to different depths and seeing what happens on the chronograph and target paper, and so far I’ve obtained my best results seating them hard, pushing them in past the point where the anvil can be felt hitting the bottom of the pocket. Doing this, I can almost always get velocity standard deviations of less than 10 feet per second, even with magnum cartridges and long-bodied standards on the ’06 case, and I haven’t been able to accomplish that seating primers to lesser depths."

Dan Hackett
Precision Shooting Reloading Guide, Precision Shooting Inc., Pub. (R.I.P.), Manchester, CT, 1995, p. 271.

[std7mag]

Is it just me, or does anyone else see the possible issue here?

Your worried about chrono results with only 13 rounds down the barrel?
Shoot 100, then get back to me.

Not knowing the condition of the bore, aka how rough it is inside, could have a fairly significant impact.

I've seen/ heard of, Rugers that don't shoot worth a darn till there is some decent copper in the bore. Like close to 50 rounds.

[Unclenick]

That may be a good catch. I didn't take "new" that literally. I assumed break-in was done first. I always clean and cool between every round for the first ten to burnish the worst rough spots. Howa's U.S. distributor believes this helps prevent heat walking by helping the stresses in a button-rifled barrel take an initial set in its cold barrel position. I still think his long wait changing POI is still a strong indicator that heat walking is happening, but stock contact could complicate that interpretation.

[Newts]

Ok, I have a little bit of time to reply.

Unclenick, in regards to the shot placement, shots 11-13 were purposefully aimed at that lower left-hand spot. It was an end of the day, 'hey, let's just see what this load might do' kind of thing. I was not taking it too seriously(shooting for groups) because of the scope I had on it at the time.

The time delay between shot 9 and 10 is when I went up to my shop to load #10. I had only loaded 2-9 for testing. The large delay between shot 10 and 11 is because it took that long to load the three rounds for the 'fun' test.

I think the first shot is so far out, and maybe the following few, is because I had just cleaned the barrel, and it was cold. Also, I really need to stress this, I was not shooting for groups - except that last three shots. Meaning, I was not in the focus on all aspects of shot control mode. I was simply just making sure that all my shots went to that general area in order to avoid hitting my chrony. Yes, I was aiming at the center spot, but not focused on it. If that makes sense?

std7mag, I had not thought about the bore roughness making a difference in velocity. If this is the case, then its a first for me. I have shot many new guns and never had this happen. I am not "worried" about velocity, just found that the results were odd. As far as the Ruger not shooting worth a darn, I'd say that it shoots right up there with some of the more high dollar guns I shot. The absolute very first rounds I fired were some cheap factory Hornady Whitetail ammo and they printed inside of an inch - with the cheap scope I had.

Also, even looking at the target and knowing I was not shooting for group size shows that this gun is actually pretty remarkable. I have shot this kind of test before and I would normally get some bigger 'patterns' on the paper. If you take shots 6-10 and measure them you'll see that it's shooting at an inch, with a 2-grain powder charge spread.

Now, I am not trying to hype up this gun as a bench rest shooter. I am simply saying for a factory gun, brand new, it is shooting very well. I hope this is all not sounding abrasive. I am just trying to throw out as much info as I can in the time I have.

One thing, Unclenick you made mention of, is the bolt lug seating. This is one of the things I found in my research - which lead me to this site - that might make some sense. Here is some pictures of the three lugs. They are not the best in the world, but what I did was mark each one, and then shot 6 times with a middle of the road 43gr charge.

Lug 1

Lug 2

Lug 3

What I found is that lug 1 is making lots of contact, lug 2 hardly any, and lug 3 just some. When I read one thread that was similar to mine, I saw that Unclenick referenced lug contact. That made sense to me. Does it still make sense?

Oh, one more thing, the case prep - all of it, even the primer seating - was done very meticulously. I was trying to avoid as many variables as I had control over.

[Jsnake711]

When i broke my barrel in i just got sone cheap imi m80 loads ands ran 60rds through the barrel before i ever started testing. Ive got thate same rifle shooting bug holes with 43gr of varget at 2.810".

Oh wow, i didn't see your last post.

[30Cal]

I'm leaning towards some of your chrony data being flakey.

Using QuickLoad, if we assume the 45gr velocities can be trusted (say 2720fps avg), and iterate the case vol some, it suggests that 45gr is right at max... I've had very good correlation with several rifles stepping up through charge weights.


Also, do another measurement of case vol with fired brass (primer in), and the case length. That would help. What you provided above puts you pretty far off the expected line of velocity.

This is at 57.2gr case capacity measured at 2.000

Cartridge : .308 Win. (CIP)
Bullet : .308, 165, Nosler BalTip 30165
Useable Case Capaci: 48.743 grain H2O = 3.165 cm³
Cartridge O.A.L. L6: 2.825 inch = 71.76 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : IMR 4064

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 85 36.00 2201 1774 31992 6537 90.7 1.420
-18.0 87 36.90 2253 1860 34075 6732 91.8 1.383
-16.0 89 37.80 2305 1947 36287 6922 92.8 1.348
-14.0 91 38.70 2357 2036 38643 7105 93.8 1.310
-12.0 93 39.60 2409 2126 41152 7282 94.7 1.272
-10.0 95 40.50 2461 2219 43824 7450 95.5 1.236
-08.0 98 41.40 2513 2314 46671 7611 96.3 1.201
-06.0 100 42.30 2565 2410 49707 7763 97.0 1.167
-04.0 102 43.20 2616 2508 52946 7905 97.6 1.135 ! Near Maximum !
-02.0 104 44.10 2668 2607 56403 8037 98.2 1.104 ! Near Maximum !
+00.0 106 45.00 2719 2708 60097 8159 98.6 1.073 !DANGEROUS LOAD-DO NOT USE!
+02.0 108 45.90 2770 2811 64048 8270 99.1 1.044 !DANGEROUS LOAD-DO NOT USE!
+04.0 110 46.80 2821 2915 68278 8369 99.4 1.016 !DANGEROUS LOAD-DO NOT USE!
+06.0 112 47.70 2872 3021 72813 8456 99.7 0.989 !DANGEROUS LOAD-DO NOT USE!
+08.0 115 48.60 2922 3128 77679 8531 99.8 0.963 !DANGEROUS LOAD-DO NOT USE!
+10.0 117 49.50 2972 3237 82910 8592 100.0 0.937 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 106 45.00 2828 2931 70894 7939 100.0 1.004 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 106 45.00 2569 2418 49611 8005 93.5 1.165

CAUTION: The following post includes load data generated by calculation in QuickLOAD software based on a particular powder lot, the assumption the primer is as mild as possible, and assumptions about component, chamber and gun geometry that may not correspond well to what you have. Such data should be approached by working up from published starting loads. USE THIS DATA AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL, nor QuickLOAD's author nor its distributor assume any liability for any damage or injury resulting from use of this information or information derived from it.

If you seat to 2.800" and come down a half grain, you'd get the same stuff.


Final note: based on barrel time (which is also supported by the target), 43.5grs ought to put you on or very close to a good node.

[Unclenick]

Newts,

It looks like you could benefit from a little locking lug lapping. You may see a shift in POI after doing it. That would be strong indicator it was important to do. If it were my gun, when I pulled the barrel to do the lug lapping, I would blueprint the receiver at the same time, but that may be more than you want to put into it.

As I suggested earlier, a second set of velocities would be in order to confirm the chronograph (what model are you using?). But maybe, rather than a different ladder or chronograph, you could just shoot a few at 42.0 and 42.5 and 43.0 so we can average the velocities for those charges and see if those averages confirm the big jump or not. That's going to be the best way to eliminate instrumentation error. One of the problems with single-shot-per-charge ladders is always the chance that an outlier of some kind will show up. It happens. The real velocity distribution is on a bell curve. The shot-to-shot inaccuracy of the instrumentation is on a bell curve. Every once in awhile the wrong extremes line up and you get a reading that's an outlier, so it would be good to eliminate that possibility.

Did you make your case capacity measurement with a fired case? I'm asking because your number was small for as-fired commercial brass.

[Newts]

Originally Posted by Unclenick

Newts,

It looks like you could benefit from a little locking lug lapping. You may see a shift in POI after doing it. That would be strong indicator it was important to do. If it were my gun, when I pulled the barrel to do the lug lapping, I would blueprint the receiver at the same time, but that may be more than you want to put into it.

As I suggested earlier, a second set of velocities would be in order to confirm the chronograph (what model are you using?). But maybe, rather than a different ladder or chronograph, you could just shoot a few at 42.0 and 42.5 and 43.0 so we can average the velocities for those charges and see if those averages confirm the big jump or not. That's going to be the best way to eliminate instrumentation error. One of the problems with single-shot-per-charge ladders is always the chance that an outlier of some kind will show up. It happens. The real velocity distribution is on a bell curve. The shot-to-shot inaccuracy of the instrumentation is on a bell curve. Every once in awhile the wrong extremes line up and you get a reading that's an outlier, so it would be good to eliminate that possibility.

Did you make your case capacity measurement with a fired case? I'm asking because your number was small for as-fired commercial brass.

Yea, I think that is more work than I am going to put into this gun.

I am using a Competition Electronics Digital Link. The case capacity was made with a new/sized case. I plan to remeasure with a fired one.

So I went ahead and did some more testing Friday afternoon. Had a little time before the sun set too low, and the wind was rather calm, so I tested 42.5gr, 43.5gr, and 44.5gr. The results were as what was expected, looks like my previous test was one of those stars align and get the outliers. Definitely new to me, and a good learning experience.

I shot them at a target set at 150yds. I shot the 43.5 first, then the 44.5, then the 42.5 last.

42.5gr avg vel was 2607fps for 5 shots

43.5gr avg vel was 2641fps for 5 shots

44.5gr avg vel was 2694fps for 3 shots, it was grouping so badly that I did not see a point to go any further.

43.5gr load actually showed promise at first. First two shots stacked on each other, then I pulled the third way out. Next one was a little low but near the first two, and the last flew out like the other. I did notice that I have some compression of the powder at this charge. I can hear a few grains crunching, so I am wondering if that contributes to this.

42.5gr was the last test of the day. Had four of them fall into a nice triangle with two in the same hole. The fifth was just a 1/2" high of the group. But that's livable grouping for a hunting rifle at 150yds.

I am not done testing yet though. I will work between 42.5 and 43.5 now.

30cal gave me some data that is making me think about trying some different powder in the effort to up my velocity. I do not want to come across as a speed chaser, but at the same time, I want to have as much as I can.

He gave me some quickloads data that predicts barrel time for accuracy nodes with different powders I think is what it is? Anyways, it was listing the IMR4064 with a 43.2gr charge. Which, I am willing to bet, is where I will find the best accuracy based on what I have seen so far.

However, I was going through the list and saw that H4895 is on up the list and would potentially give me a good bit more speed. I had not thought about using it before, but it sure would be nice if it worked because I use it for .223 and I am always looking for a way to share powders with my different calibers. I plan on trying it just to see how good the quickloads data can predict. Should be interesting.