Trouble loading 7mm mauser

[Bwana John]

I personally worry more about short tight chambers in semi and full autos rather than field headspace in modern actions(Out Of Battery beats a Complete Head Seperation) but after that Enfield swallowed a field gauge with 2 extra layers of match book cover shims I wouldn't pull the trigger, or sit next to the rifle being fired, even with no gas or other signs other than the cases were completely separating.

 

[troy fairweather]

I personally worry more about short tight chambers in semi and full autos rather than field headspace in modern actions(Out Of Battery beats a Complete Head Seperation) but after that Enfield swallowed a field gauge with 2 extra layers of match book cover shims I wouldn't pull the trigger, or sit next to the rifle being fired, even with no gas or other signs other than the cases were completely separating.

Numrich had gunsmith bolt heads for the enfields pretty common in them. I've shot a lot of crf actions which can handle to much head space better the way a push feed. But it's not good no matter the gun.

I had a rem 700 22-250 I got on black Friday for just over $200, all ammo was tight in the camber and showed high pressure early. Lucky dad had a reamer.

 

[Archie]

Primers popped easily.

That might be an indicator of high pressure. Do those primers that 'pop easily' require substantially less force to remove them? That is a sign of excessive pressure. Note the only 'loose' primers I've ever had were very easy to note.

Presuming the pressure is excessive, why? I will assume you are using the correct amount - according to the loading manuals - of the correct powder for the correct weight and constructed bullet.

Are you shortening the brass after firing? Longer than specification brass will 'wedge' at the forward end of the case, keeping the bullet from moving and causing chamber pressure to mount. You might check that aspect. Lee makes a reasonably good length checker and trimmer for several dollars.

 

[.308 Norma]

Primers popped easily.

That's kinda vague.

 

[AJC1]

The headspace issue is easily evaluated. Just measure the go gage and a couple of fired cases. This can be done with a hornaday comparater, a rcbs guage or any of the many tools you can easily make. This information is important to how you will later size the case. A long chamber in a historic gun can be treated as a wildcat within reason. Dont set the shoulder back if you have a long chamber. If it's just gone then how you deal with that between bolt and setback is up to you. I would not be inclined to deal with tolerances outside a field guage before choosing a major fix. Depending on if your a shooter or collector will lead you down different paths.

 

[DRM7997]

I use a Frankford arsenal hand deprimer and there was very little resistance. Almost nothing there when removing spent primers.

I use a digital caliper after sizing checking case length. If necessary I trim the cases on a lyman case trimmer. Then measure again. Debur cases with lyman deburring hand tools. Once loaded I check overall length again and adjust seating depth accordingly.
Once I get things were needed I check 1 out of every 5. Unless something looks wrong.

I start my loads out using correct powders listed in several manuals (Lyman, Lee, and Hornady)start at minimums. I was working up in 1gr increments. It was suggested earlier that I go in 1/2gr increments and will going forward. I started getting pressure signs with mid-level loads. I'm looking for accuracy more than anything but haven't gotten there yet because of the flattened primers.

The action on this rifle is a 98k but the barrel is an aftermarket sporter. No idea who made it. So I don't think its an old military chamber issue. The barrel is stamped 7x57 mauser.

Bore cleaned up beautifully. Didn't notice a carbon ring while cleaning. I should have new brass and go guage by next week. Found a pound of imr4350 today at a local shop.

Once I check the head spacing and everything checks out. I'm going to start over with my loads. Starting with the imr4350. If head spacing is bad it'll be going to a gunsmith to have everything checked.

Here are several pics of the rifle.

 

[bummer7]

First, that is one good looking rifle. Clean, simple, and classic style. Whoever did the sporterizing did a nice job. Second, I forgot to ask you if you had notes about the commercial ammunition you fired in the rifle? Did you notice flattened primers on them?

I am really interested in this message thread as I have been working up hunting loads for my 7x57 all year long. I will be happy to pass along my chronograph data if you want it. Some of my reloads were similar to what you loaded and tried. What you listed for your reloads are not max loads but more at the starting point to mid-range. Which is why i was surprised to see you say you had flattened primers.

 

[AJC1]

I use a Frankford arsenal hand deprimer and there was very little resistance. Almost nothing there when removing spent primers.

I use a digital caliper after sizing checking case length. If necessary I trim the cases on a lyman case trimmer. Then measure again. Debur cases with lyman deburring hand tools. Once loaded I check overall length again and adjust seating depth accordingly.
Once I get things were needed I check 1 out of every 5. Unless something looks wrong.

I start my loads out using correct powders listed in several manuals (Lyman, Lee, and Hornady)start at minimums. I was working up in 1gr increments. It was suggested earlier that I go in 1/2gr increments and will going forward. I started getting pressure signs with mid-level loads. I'm looking for accuracy more than anything but haven't gotten there yet because of the flattened primers.

The action on this rifle is a 98k but the barrel is an aftermarket sporter. No idea who made it. So I don't think its an old military chamber issue. The barrel is stamped 7x57 mauser.

Bore cleaned up beautifully. Didn't notice a carbon ring while cleaning. I should have new brass and go guage by next week. Found a pound of imr4350 today at a local shop.

Once I check the head spacing and everything checks out. I'm going to start over with my loads. Starting with the imr4350. If head spacing is bad it'll be going to a gunsmith to have everything checked.

Here are several pics of the rifle.
View attachment 938493 View attachment 938495 View attachment 938496

I cant say for sure but it looks to me like an original action put into a modern stock. The cartridge is one I really like and is the great grandfather of the 7mm08. I was always curious why that was the way insted of just shooting the original but bygones and all. I'm positive we will get this worked out in short order

 

[troy fairweather]

From what I see it looks like a a&b barrel (adams& Bennett) made by ER shaw.

In Remington brass I've gone up to 50 grain with 140s, using imr 4350, I think nolers data goes to 48gr and most other I've seen has a max of around 46gr. So drop down a few grains to start. I run at least 3.00 col.

 

[troy fairweather]

A better pic of the action would be nice.

 

[Vern Humphrey]

Bullets 140gr nosler ballistic tip, speer 140gr sp, and 139gr interlock sp. Powders used rl15 36.5grs, 748 37grs, and imr 4895 38grs. I worked up to these loads starting at min according to hornady and Lee manuals. Stopped when I saw flattened primers. I do have h4895 and I'm 3031 I can still try

RL 15 is good, 748 and IMR 4895 aren't ideal. Your loads are way below the starting or minimum loads.

Here's what's happening -- the primers are backing out, and low pressure allows them to stay out until the case slams back on them. That's why they look flattened.

 

[DRM7997]

This rifle has been my most frustrating. I started my rifle reloading 9.3x57. Couldnt find ammo. Having to make brass for out of 30-06. Learned a lot quickly about head spacing and proper shoulder placement.

I didn't keep real good records of my factory ammo. I know I shot ppu 139 and Remington. Remington was older stuff green and read box. Dont remember the grain weight on those. Guessing 175gr. I know Remington was the worst of the 2. Thats why I've started with 140gr nosler, speer and 139gr hornady.

Here are a couple of pics of the action.

 

[DRM7997]

Bummer7,
I'll try to get what I've gotten so far for load data posted later this evening or early tomorrow. I'd love to know what you're getting for velocity since I don't have a chronograph. The range I use doesn't allow anything range other paper targets. They provide the stands. Apparently people in the past were putting junk downrange and not cleaning up when done.

 

[DRM7997]

Here is what I've got written down for win748.
Case Rem-Umc once fired trim to 2.35
34grs 748
Cci 200 primer
140gr speer
3.055 cartridge length
4 shots 50yds approx 3in group.
No pressure signs

35grs 748
Everything else same
4 shots 50yds approx 3in group 1 flier
No pressure

36grs 748
Everything else same
4 shots 50yds approx 2 3/4in group
No pressure

37grs 748
Everything else same
4 shots 50yds approx 2 3/4in group
Primers flattened no other pressure signs

Trimmed cases back to 2.225
Once fired Rem-Umc
36grs 748
3.055 cartridge length
4 shots 50yds no change

37grs 748
Everything else same
4 shots 50yds no change
primers flattened no other pressure sign

Thats all I did with 748. Gave up fairly quickly because of the groupings. I should be able to get more posted later today.

 

[DRM7997]

Here's imr4895

Case ppu once fired trimmed 2.225
35grs imr4895
Cci 200 primer
140gr speer
3.055 cartridge length
4 shots 50yds approx 2in group
No pressure signs

36grs imr4895
Everything else same
4 shots 50yds approx 1 3/4in group
No pressure signs

37grs im4895
Everything else same
4 shots 50yds approx 1 3/4in group
No pressure signs

38grs imr4895
Everything else same
4 shots 50yds approx 11/2in groups
Primers flattened no other pressure signs

Case ppu once fired trimmed 2.225
37grs imr4895
140gr speer
Cci 200 primer
Cartridge length 3.00
4 shots 50yds approx 1 1/2 group 1 flier
Primers appear flattened more than normal.
No other pressure signs

Case ppu once fired trimmed 2.225
37gr imr4895
140gr nosler ballistic tip
Cci 200 primer
Cartridge length 3.00
4 shots 50yds approx 1 1/2 group
No pressure signs

38grs imr4895
Everything else same
4 shots 50yds approx 1 1/4in group
Flattened primers no other pressure signs

I stopped at this point with imr4895.

 

[Archie]

DRM, looks like those cases may have used several times. How many times? I have found no hard and fast rule (other than for some high pressure wildcats) for 'case life' in number of times fired. However, one of the first symptoms of 'wearing out' a case is the primer pocket gets loose. This and this alone can make primers flat. (Other things can flatten primers, but they provide other clues to high pressures, also.)
It happens for a number of reasons. A steady diet of heavy loads - not seeming to be applicable in this case - is one, some brands are noted (none specific I recall right now) and some lots seem to be susceptible. If you're getting new brass, I suggest you observe things carefully to see what patterns you note.