First time failure ....

[mehavey]

...using 168SMK & IMR4985 in an `06.

For decades (going back to the early 70's) my no-brainer go-to load was the 168SMK and a mid-high-40s loadout of IMR4895. I've used it in two different Springfields and a Garand (also a variant load in an M1A). Today I hit a new singularity in the otherwise "standard load" when working up a Winchester New Model-70 (FN/Browning version from their S. Carolina facility.)

Win Model-70 (March`09 vintage) 30-06
24" medium barrel: floated from receiver on out w/ square-cut countersunk muzzle crown
Win Brass - assumed QL-68.2cc (actually closer to 71.4 measured)
CCI/BR2 Primer
168 SMK (about halfway into a box of a 1,000)
OAL: 3.295" (0.010" off lands, comparator measured/adjusted each cartridge)
IMR4895 (5 rounds each, 44.0-49.0 gr)
V-II 4x12 AO Leupold scope

From start to finsh of firing sequence and leaving 3-5 minutes between shots, the above loadouts flailed all over the place: 1.5 vertical and 4 to 4-1/2" horizontal. It was amazing.

At first I thought the receiver screws were loose, then I thought the scope had come loose, then I considered that I might have a bad scope. But examining the targets from the two initial 44/45gr loads showed somewhat skidding bullets (predominently nose right). Velocities ranged from 2,370fps for the 44gr load, to 2,600fps for the 49gr load (~100fps lower than QL predicted. QL pressures ranged from ~36ksi to ~48ksi. Velocity variance was higher than normal, SD's of 19, 15, 25, 31, (then 12) but nothing that would/should produce laterally-skidding bullets that I could think of.

After the 44gr, 45gr, 46gr shotgun patterns, I jumped sequence and went straight to a boundary-value Sie165-SPBT/IMR4350/57gr hunting load that QL said would produce 2,801fps at 54,000psi. OAL was also 0.010" off lands (comparator-measured).

. . . . .Instant symmetric 3/4" group. Velocity was 2,804fps+/-03

Back to the 168SMK/IMR4895/47 & 48 grain sequence: Again the horizontal 4" stringing.

Out comes a box of some old HXP-65 Greek ammo I have a case of for the Garand: 147gr(?)/mystery-dirty powder/2,714fps +/-14 . . . . (unknown lands standoff, if any):

. . . . .Instantly symmetric 1-1/6" group.

Last, the final 168SMK/IMR4895/49gr loadout ---> another 1.5 x 4 inch wild group.

Has anyone ever run into a situation where the 168SMK failed to synch with the rifle across the board like this?

[Unclenick]

Frankly, I've not experienced that, but it's perfectly believable. If you look at Chris Long's barrel perturbing wave reflections, or even the old Audette ladder timing, the calm spots are much narrower over a range of practical barrel times than the swinging places are. The same is true for the old Audette ladder harmonics. More bad barrel times are possible than good. Working up loads in big jumps like 1.0 grain, its easy to miss them. Dan Newberry uses 0.3 grain steps for that reason, hoping to find 0.6 grain spans a couple or three grains apart, where the accuracy is good. Newberry's method is described here.

I prefer both Varget and IMR 4064 for target loads in the .30-06 for their better case fill and for 4064's more gradual change in pressure with charge (not reflected in QuickLOAD's model, but demonstrated by John Feamster in the Precision Shooting Reloading Guide).

One thing you said surprised me is your COL. 3.285" is Sierra's listed COL with that bullet, and you seem to be saying that with the bullet just 0.010" further out, you are 0.010" off the lands. Are you sure it isn't 0.100" off the lands? That would be more common among commercial chambers. If you didn't make a measuring error and you really do have a throat that short, then I would try seating 3.285" like Sierra does. A lot of guns don't shoot as well 0.010" off the lands as they do 0.020" off the lands, but this is variable with the bullet and gun. Some want 0.030" off the land and some are happier at 0.050" off the lands. A few like the bullet actually touching (but the load needs to be lower) or just 0.005" off the lands. At the other extreme, the Berger VLD's want to be as much as 0.165" off the lands according to Berger. The best distance in your gun is as individual as the powder charge. Some guns have a couple of seating depth sweet spots.

Winchester cases are the lightest made, so they have the most capacity, so your expanded cases being bigger than the QL default is no surprise. A military case in a tight match chamber comes closer to that default.

[mehavey]

Thanks, UncleNick, you are correct. Under anything but extraordinary circumstances I would never move more than 0.3-0.5gr at a time -- even in just looking for a gross place to come back and explore later. This time I couldn't find anything that looked better than 3-4 inches. Worse, it was unpredictable/non-repeatable. I've never had a rifle act like this, or this badly.

Yesterday I duplicated the 57.0gr/IMR4350 load that looked so promising (3/4") as a starting point with the Sie165 SPBT and ran it under the 168SMK. Quickload predicted 2,800fps for both of the bullets, and so I looked to see if there was some harmonic associated with the speed.

Yea verily, the 168SMK/I4350/57.0 load hit an average 2,811 and it looked like it was trying for 1-1/2" symmetrical group.

So I tried 168SMK/RL-19/59.2gr (which Quickload said was nice 105% case-fill, vibrated down to no compression, 95% burn, 2,800fps again for 52,000psi. (It actually gave me 2,784fps and another "aha!" moment with 1-1/4" symmetrical group.)

So I dropped the RL-19 down to a mid 2,650fps load ~match speed. The 168SMK began to blow up laterally again: 0.4" x 3".

Last, I ran the duplicate 165 SPBT/I4350/57.0 load that gave me 3/4" groups last weekend. This REALLY blew up laterally: 0.75 x 5"+

NOTES:
1. The (new production) barrel takes forever to clean, with crud still coming out after an hour and repeated applications M-Pro7 and KG-12. I'm half-inclined to JB-Bore compound the heck out of it to see/mitigate if the barrel so rough as to "copper up" after 15-20 rounds. (That might explain the groups blowing up over time. (My other half is inclined to run a Tubbs' Final Finish sequence to polish the roughness down.)

2. I pulled the action. It's epoxy bedded in both the rear tang & the recoil lug, and felt "tight." The barrel is free-floated all the way back to the receiver ring. No bedding (yet) under the chamber. In fact I found a strange artifact of the barrel-channel cutting machine. It left sharply-raised center ridge in the chamber area, a ridge that kinda wondered off to the left by a 1/4" by chamber's end. (That might explain the dramatic lateral stringing of the groups if the chamber/barrel and the ridge were in play.) Having sanded that ridge smooth, I'm half inclined again to bed the chamber area to anchor that portion.

3. When I check OAL/distance to lands with the Stoney point, I take five bullets and measure them five times each. The throat really is that short.

COAL Distance to Lands:
180SMK -- 3.287"
168SMK -- 3.307"
165SBT -- 3.297"
HNDY 180SST -- 3.291"

That said, I'll take your recommendation and seat every at 0.020" next time to see if that tones things down.... and set up a run with IMR4064. (I run a nice/easy 46grains of it in my `03A1, even though the Garand seems to like 4895.)



... of course when all the dust settles, it could be the scope.

[HiBC]

Likely you sanded off your problem.
I could be wrong,but generally ,a mostly round group dispersion ,could be ammo,or about anything else.
Stringing,unless it indicates ammo inconsistancy,often indicates some bedding,bbl channel,etc factor.
You might check to be sure no epoxy got in around the guard screws.The guard screws should not contact the stock.They need clearance.
I'd experiment and shoot a bit more before bedding the chamber area.
One other wild idea.Many barrels have tight/loose spots in the bore.If the bbl was cut and crowned with a loose spot at the muzzle,it will work against you.
How is the crown?

[mehavey]

Thanks, HiBC. We'll see if the stock channel "ridge" had any bearing at the chamber area next time I get out this week sometime. I'll also take the gun into Sandy Garrett to see if he can see if the throat/chamfering was correctly cut (which may/may not also answer the question as to why here is such an apparent short throat.) I've had one other instance back in the early `80s where a sharp throat angle was cutting the paper patches to pieces on a 45 x 3-1/4 Sharps. It took a Clymer reamer to fix that.)

The crown is recessed/square cut with final bevel as shown below. There are no anomalies that I can see. (Of course I am getting old).


The guard screws have plenty of clearance (with exception of a very thin "washer" of epoxy found at the top of the recoil lug screw -- so thin as to easily crumble/fold in my fingers -- gone now). NOTE TO MYSELF: I've often wondered how pillar bedding works if the guard screws are to be free.)

In medical terms, the clean barrel's "feel" on patching is unremarkable/NAD. A dry patch after firing is, of course, another story. The Tubbs bullets get here tomorrow. I'll hold the bullets in one hand and JB compound in the other and decide then....

[Unclenick]

I was composing while you posted, so some of this may be redundant:

I think you and HiBC are right about the stringing. Flatten the ridge. You may or may not need to bed the chamber, but asymmetrical contact will always be bad.

I've had heavy fouling barrels before, and they need to be dealt with. I had a Garand barrel that would lose accuracy in the middle of a match, due to fouling build-up, and would take several hours working with Sweet's 7.62 to clean. No amount of break-in or other minor polishing affected it. I firelapped the barrel and recrowned it, both. The cleaning, by patch count became 6 times easier and quicker. Accuracy loss during matches stopped.

Interestingly, the accuracy of that funky bore was always good before the fouling accumulated. At 100 yards I fired 10 rounds of 168 grain SMK loads into 0.7" C-T-C from prone position right after I first bedded and did other accuracy work on it, but while the bore was still rough. It just couldn't keep working through the build-up. The military Garand barrel blanks weren't stress relieved before rifling, and that makes a bore expand a few ten thousandths where the contour is thinner, near the muzzle. Those barrels tend to be constricted below the lower band location for that reason, and only lapping fixes that.

Varmint Al says he's given up on barrel break-in procedures. He just makes about 50 passes with JB Bore compound on a tight patch and calls it done. I forget whether or not he refreshes the compound during that, but you can search his site to see. If the barrel still seems to foul to0 fast he does a second round with Flitz, which he finds helps.

HiBC is right that you want to slug the bore to feel for constrictions. If you have them, you'll either want to firelap or hand lap the bore. Note that the Final Finish system is not a firelapping system, it is a firepolishing system that refines the bore surface pretty equally all over, and does not necessarily do anything to reduce constrictions.

Looking at your first post, you indicated slight keyholing was apparent. The 168 grain MatchKings are a little longer than the 165 grain GK boattails, so they do want a little more spin to stabilize or to go to sleep equally quickly. I'm wondering if the crown configuration isn't causing excessive initial pitch and yaw of the 168 gr SMK it is having to recover from. If you could get out to 200 or 300 yards to give it more time to go to sleep, you might see an improvement relative to the GK.

The 168 gr. SMK uniquely tends to become unstable in the transonic range, which Bryan Litz attributes to its particular boattail configuration. It's possible that muzzle blast disproportionately affects that bullet base shape. You could see if the 175 grain SMK's do the same or not. They don't share the transonic instability problem.

That leads to HiBC's other point: re-crowning the barrel. I once read something by a fellow who did a co-purchase of the Dave Manson crowning tool and did most all the rifles belonging to his rifle club's members with it. IIRC, more than half shot better afterward, including some custom barrels, so this is not an uncommon area for improvement, even when the existing crowns look good. It may be that a new crown and a sharper crown angle might make the 168's happier.

[mehavey]

...you want to slug the bore to feel for constrictions. If you have them, you'll either want to firelap or hand lap the bore. Note that the Final Finish system is not a firelapping system, it is a firepolishing system that refines the bore surface pretty equally all over, and does not necessarily do anything to reduce constrictions.

Per y'all's counsel I've gone ahead and ordered the NECO Pre-imbedded (50) Firelapping Bullet Kit that includes 10 add'l lead slugging bullets. (Do I assume correctly that the difference between the Firelapping kit and the Tubbs bullets is one of grit size? -- and to stop/proceed with polish if/when the slugging process reveals any constrictions are relieved?)

That leads to HiBC's other point: re-crowning the barrel.

Interesting point. Is there a boat-tail-forgiving/favored crown configuration to consider (for a post-Christmas next step) if required?.

Meanwhile, I'll go load up some flat base 165's for next trial

[Unclenick]

The NECO roll-your-own kit is what I bought years ago and have used to good effect. It's a combination of the grit being coarser and the bullet metal being softer so, with light loads, it doesn't bump back up to remove metal after passing through a constriction. The Tubbs FF system uses jacketed bullets that are more elastic, so they do expand back out after passing through a constriction.

You clean and slug again to check progress every 5 shots by the NECO instructions. You'll have only 10 coarse 220 grit rounds in your kit. I have used up to 20 in the Garands before the constriction was gone, but I embedded my own odd bullets and the Garands have a lot of metal to remove compared to most guns. 10 is usually enough. 20 is the upper limit. If you don't have constrictions, but just roughness, 5 will be enough. If you have a bad constriction, you may have to stop shooting at 10 and order 10 more coarse bullets. If you call NECO, I'm sure they'll sell those to you if your gun does turn out to need them.

I set aside a set of 60 old .30-06 cases for firelapping since I was going to do a number of guns in that chambering. I colored the extractor grooves with Magic Markers, using black for 220 grit, red for 400 grit, green for 800 grit, and blue for 1200 grit bullets. I didn't want the brass used with coarse bullets to contaminate the finer ones when I did other guns, and I wanted to be able to load a full set before going to the range.

I used the manual's listed minimum of 8 grains of Unique in my loads. The firelapping bullets are in the BHN 10-12 range. By Richard Lee's information in the 2nd Edition of Modern reloading, you need to keep peak pressure below about 12,400 psi to avoid exceeding the yield of BHN 10 cast bullet alloy that would permanently alter the bullet diameter, which defeats constriction removal. QuickLOAD thinks that with those 138 grain cast bullets, 8 grains of Unique will run about 10,000 psi, so its fine.

Since you are shooting bullets at a pressure so low they don't bump up, there is potential to create gas bypass and get leading during firelapping as the bullet base clears a constriction. To avoid that, since the bullets have no gas check, I add a few card wads under each bullet. Otherwise I'm concerned I'd be cleaning after every round until a severe constriction was at least reduced.

The benchresters like their 11° crowns, but with a recess you can just cut it down to perpendicular to the bore. That will have the least influence on the bullet. The sharp edges that result will cut patches pushed in from the muzzle, but since you want to clean a bolt gun from the breech, that's the way to go anyhow.

[mehavey]

Roger all.... Many thanks.

I'll post results as testing/changes show progress (hope springs eternal)

[snuffy]

Here's an alternative to the other lapping systems mentioned.



http://www.midwayusa.com/viewproduct...ductTabReviews

I used this to re-claim a 7mm mag pawn shop special that some dummy had spun a cleaning brush with steel wool in the bore. It was rougher than a cob, the 3 step process made a hunting grade shooter out of it.

I have some .308 jacketed bullets embedded to use on a .308 I have that refuses to group. I plan to only use the 600 grit to polish the bore.

Interesting discussion. Let us know how it turns out, what the problem was.

It could be used to embed a soft lead bullet for removing constrictions.

[Unclenick]

I've actually recommended against choosing the Wheeler kit for several reasons. One is that they produced their kit in violation of NECO's patent 5,378,499. NECO told me they called Wheeler on it, but the founder told them since he was a lawyer he could keep them tied up in court until it became more expensive than the product profits would ever be worth, so he was taking their IP and there was nothing they could do about it. That left a bad taste in my mouth. I know that guy's son took over, then Battenfield bought them, but it left a bad taste in my mouth and I decided Wheeler wasn't ever getting any of my money.

Second, I did download the instructions for the Wheeler lapping kit from Midway and realized immediately they had been written by someone who understood the process in principle. An illustration of a badly firelapped barrel with toolmarks left untouched in the corners of the lands was represented as a correct job. Done correctly with the right hardness lead lapping bullets that does not happen. It does happen if you try to use jacketed bullets at low pressure. If you run them at high pressure as the Tubbs system does they then press equally hard against the whole bore, smoothing it as Tubbs claims, but because it works wide spots as hard as narrow ones, it then does not straighten the bore or uniform it.

Third, about two years ago an article appeared in Precision Shooting by a fellow using a Wheeler kit on a .22 rimfire rifle. NECO's instructions warn not to use anything finer than their 400 grit compound in lapping a .22. The lands are half as tall as larger calibers. NECO did a study of their method with 27 rifles belonging to the University of San Francisco Shooting Team in which they averaged a 15% reduction in group size. The fellow writing in Precision shooting ruined his bore and got bigger groups because of the inadequate instructions had him running the 220 grit abrasives down his .22 bore.

Fourth, the NECO kit used laboratory grade abrasives that have a much narrower particle size distribution than the standard shop grade abrasives Wheeler uses. The shop grade 220 grit has maximum particle size of 102 microns, or about 0.004", or twice the height of rimfire lands. The lab grade also lacks not only the largest but the smaller particles that pack the bigger particles and cause cutting to take longer. Amateur telescope makers have long observed that lab grade abrasives cut twice as fast as standard grades because of that. The standard grades that are finer work for the single-grade firelapping methods that LBT and Beartooth Bullets sell, but it takes more rounds to finish. In my experience stepping through the NECO polishing grades, I do see copper fouling from test rounds fired along the way clean more and more easily, so I still prefer the NECO method, but even the singles can improve guns, especially for lead bullet shooting.

So, if you didn't know all that stuff (mostly its news to people) I think it is worth your time to get a copy of NECO's instructions to learn how it's done properly. You need to decide what you're going to have as a goal. I've got a description explaining the principles and how the bullet hardness is arrived at in post #2, here. There is a sort of general rule of thumb that as the bullets get softer you tend to get more tapering in the bore from the breech to the muzzle, while a little harder tends to produce a straighter bore, and still harder tends to be elastic enough to polish the bore generally. Veral Smith talks about that in more detail in his book.

[snuffy]

Nick, thanks for that info. It's too late for me to boycott wheeler, since I already bought the kit, but I won't buy any other wheeler stuff. It's just a rotten thing to do to steal somebodies idea.

Do you have a link or source for the neco kit? It sounds like their lab grade abrasives would be a better way to go. Since I cast my own boolits, I could vary my alloy to cast lead lapping slugs. I may try lapping that savage barrel rather than firelapping.

[mehavey]

"...a link or source for the neco kit? It sounds like their lab grade abrasives would be a better way to go."

Snuffy, See here:
http://www.neconos.com/category/PRESSUREFIRELAPPING-20

[flashhole]

Fascinating discussion here, and please excuse my stupid question. How do you know if your barrel has a constriction somewhere along its length that may be causing the problem?

[mehavey]

How do you know if your barrel has a constriction somewhere along its length that may be causing the problem?

As you push the lead slug through the bore, you will feel "tight" spots of greater resistance.

BREAK BREAK -- The challenge of bullet stand-off: As part of the game with this particular Model-70, I measured* Actual Distance-to-Lands (A-D2L) for several bullet types/weights I’ve got on the shelf. I then compared that data to the Reloading Manual OALs (M-OAL)for those same bullets.

Note the disparity in results from simply following the manual. (And why I get gray hair)

As a handloader I normally don't have a lot of commercial ammunition lying around, but I did have some Hornady 180SP's and (a lot) of MilSurp HXP. Those are reflected in the "Assembled Cartridge" section above. Again note the disparity between and any "standard."
(BTW-1, the Greek HXP shoots great.)
(BTW-2, Hornady recommends one M-OAL for their 180SP, and actually loads their ammunition to another.)

BTW-3 -- I'll clean up the graphic when I get home tonight


* Stoney Point gauge & a comparator

[flashhole]

All this time I thought wives and kids were the cause of grey hair.

[Unclenick]

The Greek suggests your rifle likes 0.046" off the lands. Pick up a box of the 150 grain Hornady FMJ's. I think you'll be pleasantly surprised. I load these with N135 to get the lowest muzzle pressure for use in the Garand, but they work well with a number of powders.

[mehavey]

My thoughts as well......

I'll do a quick bore slug anyway just to look for something really out of whack, and then seat the (already loaded) Sie165SPBT/4350 loads deeper to 20, 30, and 45 thousands off the lands to check before doing anything else.

[mehavey]

BTW: When I pulled the 151.1gr_HXP-68 cartridge apart, it held 52.4gr of an unidentified ball powder. If I go to Quickload, however, it would appear to be an "H380-like" variant since powder-appearance/quantity/case-fill/velocity/%burn/residue is right-on.

Since H380 meters like water, that would be a nice run-of-the-mill loadout.

[Unclenick]

H380 is canister grade WC852 which was designed for M2 Ball. So the QuickLOAD magic continues to work.