My Whelen is flattening primers...

[coop4u2c]

It is a Ruger Hawkeye SS .35 Whelen
225 gr. Nosler BT
RL-15 powder
Rem. cases trimmed to 2.494
Fed. No.210 LR primers
RCBS Dies
RCBS hand primer

I started with 20 pieces of once fired brass. Tumbled, full length resized, trimmed to max case length. Loaded 5 each with 55, 55.5, 56, 56.5 grains of RL15. Seated 225 BT to a C.O.A.L of 3.340.
Primers started to back out of the case with these loads. Read online that primers backing out could be because of a lower power round not "pushing" the case back against the bolt face. Okay, i'll try again.
Took the same 20 pieces of brass (now twice fired). Tumbled, full length resized, checked to make sure cases weren't longer than max (they were not), this time I used a primer pocket uniformer from Lyman to make sure the pockets were clean. Loaded 4 each with 57, 57.5, 58, 58.5, 59 grains.
Fired only 2 rounds with 57 gr. and had the primers flatten on both. Bolt lift was normal and no other signs of pressure.

What could cause this?

Thank-You,
Coop
View attachment IMG_4049.JPG

 

[Guest]

I'm thinking you're over-sizing the brass and pushing the shoulder back too far. Try this test:

1. unscrew your size die a few turns (or maybe 6-7)
2. Size a once fired piece of brass and check the neck to see where the die stopped sizing - don't use your twice fired brass for this
3. Adjust the die so it just sizes to the base of the neck, but doesn't touch the shoulder
4. Test fit this case into your rifle chamber
5. If it fits with little or no resistance, lock down the die and size some more cases and test fit them
6. If it feels super tight when you close the bolt, or the case won't chamber, screw the die in half a turn and resize and retest
7. Repeat the size-test-half turn-resize regimen until the brass will chamber with just a slight resistance (where you can close the bolt normally without having to "muscle it over"
8. Re-shoot the loads up to 57gr (starting at 55gr)

I suspect what's happening is you're moving the shoulder back too much, and when you fire the round, the case is moving forward in the chamber, then the primer is setting itself back, then the case is stretching back onto the primer and extruding it flat, if you follow the description there. In light of this, you'll want to use a bent paper clip to inspect your cases and be sure you don't have a groove at the webbing, indicating casehead separation.

In fact, after I posted this, I looked closer at your picture. I think I see the bright ring near the casehead that indicates you've got stretching going on. Be very careful and check this out thoroughly before firing any of those "twice fired" loads again. That brass may be trashed from the stretching.

In the future, moving forward, always set your dies up in the manner described above (commonly known as "partial full-length resizing" or "bumping the shoulder back") as it will ensure you don't have headspace problems when you shoot your handloads.

 

[glane5910]

I agree 100%, probably sized down too much creating excessive head space. If you were truely over pressuring those loads, your bolt wouldn't want to open so easily and extraction would be hard as well.

 

[coop4u2c]

Awesome! Thank-You!! Do I need to do anything with the expander/decapper to partial size? As far as the other rounds, do I need to pull the bullets and powder and scrap the brass?

 

[glane5910]

Negative on the decap. You can keep the brass etc. Continued firing with your current settings will shorten brass life. You could pull the bullets and reduce the powder charge, load the bullets long enough to just touch the lands so the case can't jump. The case will then just expand to fill the chamber.

 

[Guest]

Greg is on the money with the remedy for the other brass. I'd inspect all the "twice fired" very carefully to be sure it's not close to separation - after all, it's just two or three pieces.

 

[glane5910]

I went back and looked at those pics again and agree that they look like they have stretched some down at the web. Toss those like mentioned and go forward with the other brass.

 

[coop4u2c]

So I tried again. Used lay-out die to track my progress with partial sizing. By the time the neck was sized the die was touching the shell holder. Case fit my chamber from start to finish without resistance. Also, when I tumbled my brass (Hornady once-fired in my rifle) I noticed a distortion ring above the case head.

 

[gerry]

Sometimes the brass looks that way in my Whelen if you gave a generous chamber and undersized brass it will look that way. Did you have the same primer flattening issue with the Hornady factory loads?

 

[glane5910]

That line could just be where the die is actually sizing to. Take a micrometer or calipers and measure there and compare with a factory load. Its just not that shiney look you get with brass stretching.

 

[glane5910]

When I do a partial resize with a full length size die, I raise the ram and screw the die down to just touch the shell holder then back it off roughly 1/8 of a turn. That will give you plenty of neck tension and you know you aren't into your shoulder.

 

[coop4u2c]

Those Hornady cases have never been sized. They did not have primer push back or flatteneing either. Will measure to see if there is a difference. When i adjust the die 1/8 turn from the shellholder leaves a small "bump" on the neck just above the shoulder. Thank you guys so much for your info!

 

[glane5910]

Try one case with die backed off 1/8 turn and see if it chambers w/o any difficulty. If its in a bolt rifle, it should go right in. Then shoot a couple with the same load and see what happens with your primer problem. How far off of the lands are you with the bullets you're shooting?

 

[gerry]

The way my die is adjusted the bottom 1/8th or so of the neck doesn't get sized but there is a ton of neck to hold the bullets on a 35 Whelen case anyway Looks like you are geting everything sorted out.

 

[glane5910]

The way my die is adjusted the bottom 1/8th or so of the neck doesn't get sized but there is a ton of neck to hold the bullets on a 35 Whelen case anyway Looks like you are geting everything sorted out already.

Exactly!!!!

 

[Guest]

I'm a little late to the party on this - stupid job getting in the way of talking about loading and hunting - but I will concur that I think what you're seeing is the mark where the die sized to, not an expansion ring or case stretching. It's deceiving when you look at the first couple of pictures, but when you look at the last pic, where you can clearly see the case wall with some daylight behind it, there's no expansion "bump" along the case wall, and to Greg's point, it's not the "shiny ring of death" you'll see for impending casehead separation.

I'm curious as to the reason, but I've also had chambers where partial sizing never resulted in the shoulder elongating. I theorize that it's all in relation to the body diameter of the chamber. If that's sufficiently "tight" you won't get much expansion and then not much corresponding reduction in diameter of the body, which is where I think shoulder elongation comes from. Perhaps you have a tight body diameter and a slightly long shoulder length in this chamber. If you can either purchase or borrow a set of Hornady Headspace Bushings and a comparator body, I'd be curious to see the shoulder length dimensions on new factory ammo, fired brass, and resized brass for your rifle. I'm betting the shoulder is a little long, and the first two series of resizings through your die pushed it back a few thousandths. It would take measuring to be sure. We can "sort of" answer the question if we think about where the die was set to in the first two sizings (which flattened primers) and where it's set now. If it's the same, that's puzzling. If you had the die cranked down where the shellholder contacted it prior to the top of the press stroke, and then you cammed over into it, that would explain a bit of the issue, as that could account for several thousandths of shoulder bump and thus the primer flattening.

Please load and shoot the start charges with the now fully sized Hornady brass and post the results, if you can, as my curiosity is high on this one. It may be that you have a severe mismatch between your die and your chamber and a new sizing die is in order, but that's a very slim chance.

 

[Ridge_Runner]

A tech at sierra once told me, if using federal prmers and they have mild flattening, if no other pressure signs are present, its probably due to the fact that fed. primers have a softer cup.
I'd do the same die adjustment test except, punch a case out to 375, then size it back to 358 till it will chamber with resistance, then screw the die down 1/16th turn and lock it down, then try the same load with a rem. primer and see if it flattens, if not go back to feds and don't worry about flat primers.
RR

 

[SJB358]

Any luck figuring out your Whelen? Scotty

 

[coop4u2c]

Sorry it took so long to get back. Finally got to the range over the weekend. Loaded up some Hornady brass with the sizing die 1/8 of a turn off the shellholder, no more flattened primers (or backing out). Thank-you guys for all your help!!! Now for round 2. Accuracy is not there. About 2"-2.5" @ 100 yds. The throat of this rifle is ginormous. Using the 225 gr. BT, the length to the lands is a whopping 3.630. My magazine requires a round no longer than 3.430. Thats a jump of .200, nearly a 1/4 of an inch. Loads at 3.430 or the suggested 3.340 max so no difference on paper. Next up is 57.5 gr. to 59 gr. @ 3.430 to see if there is any improvement.

 

[SJB358]

I have a long throat on my Whelen as well. I seat both the 250gr PT and Speer 250 at 3.34" and get excellent accuracy using RL15. I could load longer if needed, but right now, I have no plans to change. I think as you progress up the powder charges you will start bringing your groups in. Scotty