Need some help with a verdict on some test rounds

[Jbotto]

Here's the data:

.223 Rem
PMC brass
CCI 400
60gr Hornady V-max
26.0gr Varget
COL: 2.303"
Shot from a Stevens (Savage Arms) 200

This load is experiencing some cratering around the firing pin mark. My book lists 27.2grs as the mas load. These loads are compressed. I loaded up 20 of these and fired 3. All 3 cases show a small amount of cratering. So what other information is needed. Some people have said they are cratering simply because of the soft CCI400 soft cup, others are saying they are above Hornady's information. Any help? Should I shoot or pull the rest of these? Should I seat them deeper to Lyman's suggested 2.260" and try them out again? Thanks for any and all help in advance!

[Brian Pfleuger]

How far are you from the rifling at that OAL?

What is the gun? Some guns will crater primers at milder loads due to a chamfered firing pin channel. (Rem 700 maybe? I can't remember for sure.)

CCI primers might be "soft" compared to Mil-Spec primers but they're among the hardest "normal" primers you can get.

I've crated them in a Ruger and a Savage but never at/under SAAMI pressure.

[Jbotto]

I updated the original post with the forgotten information of rifle used. Too poor to afford a chronograph yet as well so no velocity information. I can't find my information on the rifling with this bullet at this time. I'll find that information after work tonight and get back to you Brian.

[Jbotto]

I guess I don't have the distance to rifling with this rifle. What next might you suggest?

Tonight I took and seated a few of my remaining rounds deeper and closer to book length. I've always seated a touch longer than book but it all depends on the bullet I use I guess. I might get out and test one of each seating depth tomorrow to see if the cratered primers go away change in some way.

[Brian Pfleuger]

I would suggest finding out where the rifling is. With a slight change to case capacity so the numbers make sense (QuickLoad is awfully low for .223 capacity), QL, thinks that load would be between 46,000 and 58,000psi, the higher being if you're jammed in the rifling. But, if your case capacity is low, you could be in the 60s for pressure.

I'd like to know the case capacity in H2O of a fired, unsized case, if you can. Put a tiny drop of dish soap in a glass of room temperature water and stir it in. Very tiny drop, no bubbles, just enough to break the surface tension. Put a case on the scale and zero it. Fill the case with water up to the neck. Tap/snap the sides of the case to remove any air bubbles. Fill it the rest of the way, so the water is "flat" on the mouth, no "bump" up or down in the water.

What is the weight? For a "sanity check", your number should be somewhere between 28 and 32-ish.

[Jimro]

Drop down between 24 to 25 grains. I think you'll be happier with the accuracy.

Jimro

[SL1]

You stated "my book" showes 27.2 grains as max, but did not tell us which book that is nor what bullet was used for that data.

Hornady lists 24.9 grains as max, using a COL 0f 2.250 for the V-max. Hornady does not indicate % loading density or when loads are compressed.

Hodgdon's manual showes data for the 60 grain V-max with the same COL as Hornady, giving max at 27.0 grains and indicating that it is a compressed load producing 51,900 CUP. Hodgdon's start load is 25.0 grains and is NOT indicated as compressed, producing just 40,400 CUP.

So, from this I conclude that you must have lower capacity cases to achieve compression at 25 grains with a COL of 2.303". Hodgdon and Hornady were both using Winchester cases, which seem to have a little more capacity than PMCs in my limited experience. Hodgdon and Hornady both used Winchester SR primers, too, so the difference in their pressure results may have been due to different measuring techniques (CUP vs psi) or just different lots of powder, primers, etc.

If I were you, I would NOT just seat the bullets deeper on the same charge and try them to see what happens. I would reduce the charge to where it is just not being compressed with a 2.250" COL and see if that still craters the primers on a few rounds. If not, then I would independently work the length and charge back up in steps to see what starts cratering the primers. But, if the uncompressed charge at 2.250" COL still craters primers, I would seek a chronograph's help before deciding what to do, next.

SL1

[jepp2]

From the Nosler manual, using Nosler brass loaded to a 2.260" OAL, starting load is 22.5 gr (88% fill) mid load 23.5 gr (92% fill and the most accurate load tested) and max load is 24.5 gr (96% fill).

When you sized your brass, now much did you set the shoulder back?

All 3 cases show a small amount of cratering.

Have you previously loaded for this rifle? Might give you an idea if the cratering is meaningful or just noise. Are you using any other indications of excessive pressure? Personally I find many others to be more accurate than reading the primer tea leaves. Just impacted by too many things.

[Jbotto]

Brian, I'll do the water capacity test tonight, using one of the three cases I've fired using this load, if that's ok.

SL1: My Lyman 49th shows the 60gr Vmax as the bullet they use to represent 60gr .223 loadings. With a starting load of 24.4grs of Varget and a max load at 27.2gr, showing it is compressed at that max. My Lee manual states a 60gr bullet and Varget with a starting load of 25.0grs and a max load of 27.0grs, also showing it is compressed. I also am trying to find the solution to this load of mine which is a 26.0gr load instead of the 25.0gr load that you indicated. Thanks for the other information though! I'm interested in finding out what is going on here. I might just plan to pull them and drop down to my previous sweet load with this combination.

jepp: Brass was neck sized using a Lee Collet die. I have loaded for this rifle for the past 2 or 3 years. It's never flagged loads at a full grain under max before, with a few different powders.

Thanks to all who are taking the time to respond with information and wisdom. It is very much appreciated!

[Bart B.]

If there's a few thousandths clearance around the firing pin tip to the hole in the bolt face, safe loads will crater the primer. When this happens the dimple depth in the primer is decent.

So will a weak firing pin spring cause primer cratering if it's just strong enough to fire the primer but not stron enough to stay forward to prevent cratering. Primer dimple depth will be shallow when this happens.

[Jbotto]

Alright Brian, tonight I finally got around to checking the water weight of the 3 fired cases. The weights came out to 30.8gr, 31.1gr, and 31.1gr. with an average of these three right at 31grs. I had never performed this test before and think I did it to the best of my ability. What's next?

[Brian Pfleuger]

Ok, that number is very reasonable for PMC brass, from what I read.

QuickLoad agrees that the load would be slightly compressed.

If you've got that jammed in the rifling, you could be around 60,000psi. If not, you should only be around 50,000.

The next step is to verify the rifling distance.

[SL1]

Brian,

Maybe you should give Jbotto a range of pressures, based on a range of actual burning characteristics that can occur with different lot numbers of the same powder. I know that QuickLOAD provides that with +10% and -10% values on the Ba parameter (under the tabulated data in the "Charge Variations" window). But, I think that + and - 5% is more realistic. Jbotto MIGTH have a hot lot.

SL1

[Brian Pfleuger]

That's true.

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge:

If you're off the rifling a reasonable amount,

45,948-55,108psi

If you're jammed in the rifling:

55,417-64,638psi

[Jbotto]

Alright, what's the best way to measure distance to rifling?

[Brian Pfleuger]

Well, a Hornady OAL Gauge is probably the best way.

Alternatively, and in the mean time, use your collet die to size a case so it holds a bullet fairly well but it's still movable without a whole lot of force. It should be "stiff" but not put a hole in your thumb when you press on it. If you have Redding body dies, use it to size the case so the shoulder is setback about 0.001-0.002 for proper headspacing and so the case will fit smoothly in the chamber. Otherwise, use a once fired (in your gun) case.

Seat a bullet very long, just enough so it stays in the case.

Remove the bolt and slide the cartridge into the chamber. Gently tap on the head to ensure that it's seated against the chamber shoulder. Use a wooden dowel or a cleaning rod with a flat end (I cut the pointy part of a patch jig that comes with most cleaning kits), slide it down the barrel, GENTLY push the cartridge out of the chamber.

Repeat for consistent results.

That should be a very close measurement to actual.

[Jbotto]

Alright, I can give that a try. Why not just chamber the dummy round and then extract it with the bolt?

[Brian Pfleuger]

You can try that too. The potential downfall is that the bullet is stuck in the rifling and you're pulling on the case. The case could move on the bullet before the bullet pulls out of the rifling. The opposite is possible with the method I describe, the case could hang up and the the bullet could push into it but it's less likely.

[jepp2]

I use the rod shown in the bottom of the picture. Yes, I know it is to the tip, not the ogive, but the variation isn't an issue for me. I always load my OAL based to the tip of the bullet.

[rduckwor]

Another thing to consider is that primers are a poor pressure sign for the reason others mentioned above. Ejector wipe and/sticky bolt lift are better indicators. Look for a shiny pot on the base of the fired cases. If you find one, you're likely too hot. Likewise with a sticky bolt that is difficult to lift. Don't rely on primer appearance alone.

Good luck.

[Jbotto]

Well I don't know what I did wrong, but that was highly inconclusive. My lengths ranged from 2.364" to 2.407"... I'm starting to get discouraged enough to pull the last 17 and drop back to my standby charge and be done with it. I don't have the cash for a Hornady OAL guage at this time, so that's out.

[SL1]

Jbotto,

Here is a cheap way to get the length of a cartridge where the bullet just touches the lands. But, you will need a friend or have a third arm.

Use a cleaning rod that is long enough to touch the beach face from the muzzle, preferrably with a flat ended tool on the tip. (I cut-off a plastic jag in a drill.)

Close the bolt and push the rod down the barrel from the muzzle with some tape on the rod approximately were the muzzle will be when the rod stops. Hold a flat razor blade against the muzzle and use it to cut through the tape by twisting the rod. It helps to have several thicknesses of tape.

Now, remove the rod, open the bolt and gently push a bullet into the chamber throat, holding it gently against the rifling with the eraser end of an pencil. Put some more tape around the rod about where the muzzle will be when the rode stops against the bullet's nose. With a friend holding the pencil to keep the bullet in place, insert the rod down the muzzle until it stops against the bullet's nose. Use the razor blade to mark the tape on the rod.

Now, withdraw the rod and measure the distance between the two razor cuts on the tape. because the tape is soft, this is not going to be a +or- 0.001" measurement, but should be good to something better than 0.01". Because of variances in the shape of bullets from the same box, that is probably about all you can really expect to get when loading, anyway.

You can now use the SAME bullet to set-up your dies to get bullets seated to the same distance from the lands, or a different distance of your choice. The important thing to understand is that you will be measuring over-all cartridge length to the tip of the bullet, but the dies are working to the point on the ogive of bullet that touches the rifling. If you change bullets, the next bullet might have a different tip shape, so the distance off the lands would be different for the same cartridge over-all length with the other bullet. So, the bullet you use to take the measurements with the tape must become part of your defacto length standard definition. By seating that bullet to different COLs with different die adjustments, you can effectively seat other bullets to different distances from your gun's rifling.

SL1

[Jbotto]

Thank you SL1 for that information. Very good stuff you posted. Don't have a third arm at the moment as I live alone in a college town. And since it's summer, most everyone is gone. I'm thinking of just pulling the last 17 and saving the bullet and possible pressure issues on my rifle. When I have some help or resources for some new reloading gadgets, I'll give this a try again. Thanks everyone for your help! It is all very much appreciated!