Brass pressure problems in Mauser build

[kfd518]

I posted this in my thread about this rifle build but I feel I might get better answers in a separate thread.

Hornady 200 gr factory ammo rates at 2910 fps was running 3040,3039,3081 fps. Primers flattened.
49 grs of reloader 15 with Speer 250 hot cor, WLR primer was 2360 primers pushed and flat.
When inspecting cases after getting back home and taking measurements I noticed a ring around the casemouth on all fired cartridges reformed from 270 and the hornady factory 35 whelen. This ring mic'd at .3870 the neck below this ring is .3885-3890. I can feel said ring with thumb. Is this a tight spot from reaming the chamber?this is the First time rifle has been fired.
What might have caused this ring?

I cut the chamber myself, bolt closed 2/3 on no go but would not close completely.
Chamber was cut with elk ridge reamer rentals 35 whelen mfd by PT&G.
Brass length 2.4925 hornady and reformed 270 is 2.4795

[vzerone]

Too bad it was a rental reamer, you could examine the reamer at that point. Primer flatness is not a guaranteed indication of safe and unsafe pressures. The fact alone primers vary in softness tells you this. To really know you need a pressure measure device such as a strain gage.

I wouldn't do anything to the chamber until you thoroughly investigated it and find the cause exactly.

[kfd518]

Yeah and no telling where that reamer is now or if it has been sharpened since then or incorrectly before I had it. Cero safe seems like a good next step i guess. The velocity of the hornady rounds seemed a bit to warm considering the advertised velocity. I believe I will check firing pin protrusion as well. Almost seems as they are getting pushed to far in the chamber somehow looking at how far backed out some of the primers were. That and possibly rougher than I though chamber walls.

[vzerone]

You could do a pound cast too instead of cero safe. If you had a bore scope you could get a good look at it too!

[kens]

is that some leftover bullet crimp??

[MostlyLeverGuns]

What sort of throat did the reamer cut? What is the chamber length, bolt face to end of case neck? A short necked chamber (per kens) or a too short or too tight throat can bump pressure.

[kfd518]

Hornady had a very slight roll crimp but nothing like what that. And did not appear to be any crimp on the reformed re-sized brass. There is not a crimp on any of the other brass.
As I stated earlier it is from elk ridge reamers. It showed to be a finish cut Saami spec reamer.
Looking at the reformed 270 It almost appears that when the firing pin strikes it is sent to far forward, jamming in the throat ever so slightly. When I am home I will measure primer protrusion vs case mouth neck ring depth.

[Larry Gibson]

"Hornady 200 gr factory ammo rates at 2910 for was run 3040,3039,3081 fps. Primers flattened."

A 35 Whelen?

[vzerone]

Get with the program Larry, it's their Superperformance ammo line.

https://www.hornady.com/ammunition/r...performance#!/

[vzerone]

Hornady had a very slight roll crimp but nothing like what that. And did not appear to be any crimp on the reformed resided brass. There is not a crimp on any of the other brass.
As I stated earlier it is from elk ridge reamers. It showed to be a finish cut Saami spec reamer.

Looking at the reformed 270 It almost appears that when the firing pin strikes it it sent to far forward, jamming in the throat ever so slightly. When I am home I will measure primer protrusion vs case mouth neck ring depth.

So you're thinking that reformed 270 brass isn't head spacing on the shoulder datum line? If it is it would have to be one heck of a powerful firing pin spring! That Mauser claw would have a hold of the case too.

[kfd518]

I was actually thinking pin pushing all cartridges forward not just reformed. That claw is what has been getting me, because some of the primers are backed out a long way. But what you stated has crossed my mind as not possibly being the case as well. It is a brand new extractor as well. Need to take some measurements of unfired new brass resized and fired.
No pierced primers either which tells me pin protrusion shouldn't be it either. No bends in the rim either

[vzerone]

Strange, the number one thing when you see primer protusion in high pressure loads is exess head space, but that's not it in your case. You would think that the case is pushed back against the bolt face by the pressure and would reseat the primer. Have you fired any cases that were fired once, but neck sized only? That would tell us the case is snug in chamber and eliminate some things we have to thing about.

[runfiverun]

I'm thinking your case mouth is catching at the end of the chamber.

[vzerone]

I was going to ask if you trimmed them to the correct length?

[Multigunner]

Try military spec .30-06 cases, they should have a tougher shoulder.
Before they strengthened the 30-06 case shoulders simply rapid bolt manipulation could shorten the base to shoulder dimension up to .006". In the Marlin MG the action cycled with such force that the case mouth became restricted and caused excessive pressures and blown primers and separations. They set back the shoulder of the chamber to compensate.
Necking the .30 case up to .35 reduces the area of contact at the shoulder quite a bit.
Improper annealing of the neck can soften the shoulder as well. I had that problem with some 7.92 cases many years ago with similar though more pronounced effects.

But I guess you already know all that.
When the .35 Whelen first became popular it was recommended that only mil spec 06 cases be used since these were made stronger for use in autoloaders and MGs.

My .02

Try trimming a few cases about .006 or so below min spec, no shorter though.

[M-Tecs]

When inspecting cases after getting back home and taking measurements I noticed a ring around the casemouth on all fired cartridges reformed from to 270 and the hornady factory 35 whelen. This ring mic'd at .3870 the neck below this ring is .3885-3890. I can feel said ring with thumb. Is this a tight spot from reaming the chamber?

http://saami.org/specifications_and_...tion/index.cfm

The ring will be from a miss-ground or damaged reamer. Contact the rental company and have them send you a free usage replacement. Normally I have all my reamers custom ground in carbide with oil groove bushing. When I need an a one use reamer I order HSS and use it once and sell on ebay. Not really anymore hassle and normally more cost effective.

[vzerone]

http://saami.org/specifications_and_...tion/index.cfm

The ring will be from a miss-ground or damaged reamer. Contact the rental company and have them send you a free usage replacement. Normally I have all my reamers custom ground in carbide with oil groove bushing. When I need an a one use reamer I order HSS and use it once and sell on ebay. Not really anymore hassle and normally more cost effective.

I'm glad the poster didn't rent a reamer from 4D Rentals like I did. I had already used the reamer and sent it back and was reading on the internet reviews on 4D how Fred out there calls you and tells you that you will have to pay some on the reamer you just used because he tells you it came back and was in much need of sharpening. They said he has the reamer and there's no way you can inspect it. I goes "Nah" and sure enough later on that week I got a call from him saying what they posted. I just paid him the additional and was polite. That's it for him. From now on I'll just buy a new reamer and do as you said sell it.

I think the OP got some good advice here and should be able to resolve his problem.

[Larry Gibson]

Get with the program Larry, it's their Superperformance ammo line.

https://www.hornady.com/ammunition/r...performance#!/

Well, duh....no kidding Sherlock......

It was a rhetorical question. The implication being that was awesome performance from a 35 Whelen. Apparently the implication went over your head.

[Larry Gibson]

I'm thinking your case mouth is catching at the end of the chamber.

kfd518

I concur with runfiverun. That's what it appears to me also. Are the formed cases a "crush" fit when chambered or did you just FL size in the Whelen die?

[curator]

A few decades ago, I built two .35 Whelen rifles using M98 actions. I had a lot of problems with headspacing/pressure signs/primer flattening with converted .30-06 brass. I was lucky to get 2 or 3 reloads before signs of incipient head separation would show. Military brass would give a few more reloads but problems would show up anyway. Ultimately, these rifles found new homes and I gave up on the .35 Whelen concept for several years. After seeing an ad for "reamer rentals" in .35 Whelen Ackley improved, I got the bug again and built another using a E.R. Shaw 1 in 14" twist barrel and a late Springfield '03 action. The Ackley Improved version has a sharp shoulder that resists set back. My "new" .35 Whelen Ackley Improved rifle does not have the problems of the older versions. Even reformed .270 Win. brass lasts 10 + loadings, primers look normal. I do fireform "new" cases with a medium load and bullets seated out to require a bit of effort in chambering. The Ackley improved version seems to be the fix for the common .35 Whelen woes, at least for me. The '03 Springfield action also allows for longer bullets/seating depth as well.