375 Win Primers Backing Out (with pic)

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CBinNH
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375 Win Primers Backing Out (with pic)

Post by CBinNH »

I think this was addressed before, but I would like to hear
from anyone with similar experience. I have a Model 94BB.
Factory 200 gr loads shoot fine but the primer backs out.
My reloads with using RL7 or H4895 powder, Hornady 220FP
bullet & CCI 200 primers seem OK. Should I be worried?
Reload on left, factory load on right. Thanks, Chris
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colo native
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Post by colo native »

to much headspace...
Buffboy
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Post by Buffboy »

Colo native is right, but: You can also get this affect with a properly headspaced rifle and a low pressure load so your headspace "could" be fine. I've seen both, so the only way to know is to check the headspace with the proper gages.

There is a way to check this without the gages but I only have a general idea how that works(CRS) and someone else will have to give you the description on how that's done.
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colo native
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Post by colo native »

it can be done with automotive plasti gage, purchaced from local auto parts store..
CBinNH
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Post by CBinNH »

I wondered about the headspace but it seems funny that my reload primers seem OK. Maybe the factory loads are low pressure as Buffboy says is a possibility. Thanks for the replies. Chris
big bear
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Post by big bear »

I had that problem with an old Win71. I found out the tang was slightly bent, probably the same horse wreck that had broken the stock. My gunsmith straightened it out and no more primer problem I guess the action didn't close as tightly as it should have, leading to increased headspace. just a thought, before you get carried away or depressed about major issues with the rifle. Warning, I'm an old gun nut but not by any means do I profess to be an expert.
Noah Zark
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Post by Noah Zark »

Buffboy wrote: . . . You can also get this affect with a properly headspaced rifle and a low pressure load so your headspace "could" be fine. I've seen both . . .
+1. Seen it both ways myself. The fact that your reloads DON'T cause the primers to back out tells me it may not be headspace but a weak load.

Noah
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Post by Leverluver »

Could be the other way around on pressure also. The factory round is full pressure and the case grips the chamber walls and keeps the case in place while the primer alone comes back. The handload might be lower pressure and the case does NOT grip the walls, allowing the case and primer to come back together. In either case, the primer cannot come back at all unless there is "extra" head space. Whether it is excessive (beyond SAAMI spec) head space can only be told from measurement. You can get a general idea by measuring the fired factory case length just off the primer and then over the primer. Subtract the two and you will have an idea of what you are working with. If it is more than .005, yes I would call it excessive.
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Griff
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Post by Griff »

Also measure that factory rim thickness. If that brass is outta spec it's the same effect as excessive headspace.
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Post by Nath »

For me Griff has a valid point, if your reloads have the slightest lube on them the case could set back and the dry factory case stick in the chamber. It could just be that most cases grip the chamber but as pressure drops the case lets go and comes back a touch and may be the factory ammo in question here aint. How'd it shoot? If ok whats the worry?
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Post by Leverluver »

Yup, certainly meassure the factory rims but since the only company that makes 375 Win is Winchester, I doubt there is much difference. The fact is that factory rifles are head spaced generous to handle the worst case of ammunition and even a little powder fouling getting in the way. In general, the spec will fall into an area that will give .003 to .006" extra head space and if any one's rifle falls into that area, don't expect the facory to do anything about it as it DOES fall within the allowable spec. Take a look at the rim spec on any reamer drawing of the 45-70. No matter the manufacturer, you will see the spec as .070". Most casings measure .064" to .066" so there is ~.005 build right in. When reloading bottle neck cases, an astute reloader can take the "extra" head space out of the euqation. With rimmed cases, that is nearly impossible to do without some gunsmithing. All my rimmed case rifles have a little "extra' head space except my Shiloh which is head spaced so tight that if the least amount of fouling gets under the rim, the breech won't close. That's a little too tight. In a perfect world, .002" would be about right. So when pressures change, you should probably expect some unusual appearing cases such as yours.
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handirifle
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Post by handirifle »

Leverluver wrote:Could be the other way around on pressure also. The factory round is full pressure and the case grips the chamber walls and keeps the case in place while the primer alone comes back. The handload might be lower pressure and the case does NOT grip the walls, allowing the case and primer to come back together. In either case, the primer cannot come back at all unless there is "extra" head space. Whether it is excessive (beyond SAAMI spec) head space can only be told from measurement. You can get a general idea by measuring the fired factory case length just off the primer and then over the primer. Subtract the two and you will have an idea of what you are working with. If it is more than .005, yes I would call it excessive.
I'm not 100% sure that's true. My 200gr factory loads clock a full 300fps below my reloads that are below full house Hodgdons recommended load levels, with H4198.

It's been my experience that Win has them loaded down so as to be safe in marlins. The Winchester BB is a stronger built rifle.

This is copied from the online Hodgdons reloading data.

200 GR. SIE JFP Hodgdon H4198 .375" 2.530" 35.0 2288 36,900 CUP 38.0C 2480 50,600 CUP

Mine clocks over 2400 with 37gr of H4198. Heven't tried 38. But my factory loads average right at 2135fps. BIG difference.
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TedH
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Post by TedH »

You can get a rough idea of the headspace by cutting small circles of masking tape and putting them on the end of the case and try chambering them. If one layer chambers easily, add another one till resistance is felt, then measure your tape thickness.

I'd bet your headspace is fine and those factory loads are just lower pressure. Good idea to check it out though.
colo native
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Post by colo native »

just from the pics the head space IS OUT OF SPECS... end of story, seem to many of these, It may be in factory specs though, but still outa specs for a old fanny burp like me... end of story... bet it aint a pre 64>>
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Post by txpete »

:D pre=64 375 win BB 94 now thats FUNNY :D .

I think the problem is the fac. ammo also since your reloads look fine.
how old is that ammo????maybe a bad lot factory primers???.
I would pull a bullet on the fac ammo and and give the powder the sniff test.next I would use the brass/primer and reload it with some RL-7.
just some ideas :D
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RSY
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Post by RSY »

Very common for that rifle. I have one and it does the same thing. It's nothing to really worry about. Your own picture pretty much answered your question. The factory 200-gr loads are woefully understoked compared to what a respectable handload will do.

Good luck,
Scott
CBinNH
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Post by CBinNH »

Appreciate the input gents. It shoots my reloads better than factory loads, accuracy-wise. I guess if it bugs me enough, I'll see if a rifle builder a couple towns away can shoehorn a headspace check into his schedule.
Chris
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Post by RSY »

CBinNH wrote:Appreciate the input gents. It shoots my reloads better than factory loads, accuracy-wise. I guess if it bugs me enough, I'll see if a rifle builder a couple towns away can shoehorn a headspace check into his schedule.
Chris
You may think about investing in a couple of gauges, yourself. Forster sells some good ones. Get a FIELD gauge and a NO-GO gauge, at least.

That gauge will be a lot of bang for the buck since you can use it in anything with the same casehead: .25-35, .30-30, .38-55, .375 Win., etc.

Good luck,
scott
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Post by Hobie »

Not enough info, what is your reload with RL-7? With H4895?
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Post by QuarterChoke »

OK, one more time. SAAMI spec for rim thickness is .063" with a tolerance of -.010". Chamber headspace is .063", with a tolerance of +.007". Thus, there can be a slop in the headspace fit of .017", and still be within spec.

The M94 has a spring-loaded plunger ejector which holds the cartridge as far forward as the rim cut/rim thickness will allow.

Upon firing the primer develops internal pressure which sets the cup to the rear against the bolt face. The powder develops pressure which presses the sides of the case against the chamber wall, and gives a thrust to the rear. If the thrust to the rear overcomes the friction with the walls and pressure from the ejector spring, the case will move to the rear and reset the primer flush with the case head. Lubricant of any type on the chamber walls, or left-over sizing lube, can affect the friction between the brass and the chamber.

On top of all of the above, the M94 has some spring to the action due to the rear lockup.

Small primer setback is not unusual with this rifle. The only way to check the headspace is with an accurate FIELD gauge. The GO gauge signifies that the chamber is reamed sufficiently to accommodate a maximum size cartridge. The NO GO gauge is used to assure that the chamber has not been reamed too far. The FIELD gauge is used to check a rifle which is in use, and assures that wear has not rendered the gun unsafe.
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Post by Noah Zark »

colo native wrote:just from the pics the head space IS OUT OF SPECS... end of story, seem to many of these, It may be in factory specs though, but still outa specs for a old fanny burp like me... end of story...

Not quite the end of the story. Could be stacked tolerances of the rifle's headspace, and the cartridge headspace. One's a little long, the other's a little short, and there you go.

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CBinNH
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Post by CBinNH »

RL-7 & H4895 loads are both 36 gr. Neither max by my load manuals, but within 2 gr of being so. It is about as much as I care to compress the powder in trimmed cases. The RL-7 is the best so far. Chris
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Post by Lefty Dude »

txpete wrote::D pre=64 375 win BB 94 now thats FUNNY :D .

I think the problem is the fac. ammo also since your reloads look fine.
how old is that ammo????maybe a bad lot factory primers???.
I would pull a bullet on the fac ammo and and give the powder the sniff test.next I would use the brass/primer and reload it with some RL-7.
just some ideas :D
pete
**do not think that win hasn't turn out some bad lots of ammo in the past**.
There can never be a Pre-64 Win BB 94. The round was not developed then.
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