Winchester rim thicknesses WOW?

[charger 1]

You know its something I never even considered before,but yesterday I took out a wack of new rimmed cases,45/70 and 348,stood um up on the suface plate and gave em a go with the height gage.....013" difference..Dont these fellas primarily headspace off the rim? Well I guess completely in the 45's case. Man those tolerances aint great

[Bass Ackward]

Since a primer requires a repetive and equal force to produce a consistent spark, what do you think that does to ignition?

[Maven]

Charger & Bass, Now that's something to ponder: Segregate cases by weight AND rim thickness to see if the latter affects mean velocity + SD & ES and accuracy (target dispersion). On the other hand, maybe I just have too much time on my hands.

[joeb33050]

Is this a difference of .013" in rim thickness from case to case of one type, or from 348 to 45/70?
See C. Dell's tests that show that the force of the blow on the primer doesn't affect mv. 6.3.1 in the book.
joe brennan

[charger 1]

Is this a difference of .013" in rim thickness from case to case of one type, or from 348 to 45/70?
See C. Dell's tests that show that the force of the blow on the primer doesn't affect mv. 6.3.1 in the book.
joe brennan

348<>348 my brother. .068 down to .055 all in the same bag....Not only is win inferior to RP in their ability to send out unmangled big bore brass,its not as malliable and now this. My worry was not the wack of the primer,but just how are these things supposed to headspace consistently,ecspecially in say a falling block with no forward thrust. I would say that if anyone has a ruger #1 in 45/70 and he's using win brass ,if his accuracy is in the crapper he may wanta look at this as a possible concern

[kenjuudo]

Separating .22 rimfire by the rim thickness will improve groups enough to be worth the bother for target work, but not enough to matter popping squirrels.

jim

[Bass Ackward]

My worry was not the wack of the primer,but just how are these things supposed to headspace consistently,ecspecially in say a falling block with no forward thrust.


Charger,

In my work, when I get different hammer blow strength, I get wild ES. And with poor headspace, you need to run much faster powders to get consistent ignition or lower ES loads.

I have seen it in rifles with Savage actions where the strength of the firing pin spring is adjustable and I have seen it in handguns. When I started with my new 458X2, I was getting ES of 150 fps with a load. I adjusted the firing fin spring tighter and ES dropped to 23 fps.

I tightened handgun headspace by removing the end play in the cylinder. This holds the cylinder back against the back of the frame. It improves headspace. And this improved ES down to low double to single digits in that gun. 44man has written here of changing hammer springs on his handguns just to get accuracy to come back.

So consistent firing pin blow that starts with headspace is everything to consistent ignition. If you don't hold the cartridge case, and thus the primer in the same location every time, how can you possibly be getting the same ignition?

[drinks]

Rim thickness is not the only variable, I once measured 10 different cases, all for large rifle primers, and the depth of the pocket varied from .124" to .138", .130" is the height of a large rifle primer.
With this, you can run from slamfires to misfires, depending on the length of the firing pin, amount it protrudes and where the stop is adjusted to.

[Bass Ackward]

Drinks,

Absolutley. I forget to consider that because my pockets are uniformed as a part of the "new" brass ritual.

We tend to over look the stuff "we do" when we are on autopilot. Good point.

[six_gun]

I had a problem with some new Winchester brass and misfires with my Hornet barrel on my Contender. I traced it to the differences in rim thickness and contacted Winchester. Their solution was to attack me for not knowing what I was doing. I solved the problem with Remington brass. The rim thicknesses were very consistant and no more misfires.

Sounds like Winchester rimmed brass is still having problems.

Six_gun

[charger 1]

I had a problem with some new Winchester brass and misfires with my Hornet barrel on my Contender. I traced it to the differences in rim thickness and contacted Winchester. Their solution was to attack me for not knowing what I was doing. I solved the problem with Remington brass. The rim thicknesses were very consistant and no more misfires.

Sounds like Winchester rimmed brass is still having problems.

Six_gun


Agreed Bro. Overall I'm a way bigger fan of RP brass for that and many more reasons but when your shootin 348, you is stuck

[KCSO]

For serious target shooting I will start with 100 cases of 45-70 and I amy get 20 matched users. To give you an idea of how much difference firing pin force will change grouping I tested a Winchester lever rifle with a rebounding hammer. Groups strung 4-6" and when the rifle was converted to a standard hammer and spring the stringing disappeared and groups shrunk to 2 1/2".

[dahermit]

Winchester had a problem in the late 60's with a large variation in rim thickness in the .44 special. Seems as though they never cured the problem. I have found the same problem in .44 special rims from Winchester in current brass in .44 special and .357 mag.

I no longer buy Winchester brass.

Regards,
dahermit