Case Length

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TJLeGault
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Joined: Fri Sep 12, 2014 9:21 pm

Case Length

Post by TJLeGault »

The chamber length, measured with calipers of my Shiloh 45-70 Sharps is 2.125, measured from the breach to the step inside the chamber.
My Starline brass is 2.087 so its .038” short. All of my brass is short. The longest is Winchester but it still a bit short. My Speer reloading book even gives a trim to length (2.095) that is too short for my particular rifle as I measure it. My question is, should I buy 45-90 brass and cut it down to be 2.125? It seems to me I should but I wanted to hear what you guys think.
Thanks
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desert deuce
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Re: Case Length

Post by desert deuce »

Have a case of 500 Remington Factory unprimed cases, most are in the 2.080 area. I annealed the front inch of 150 and then put them through the case stretcher. (My #1 least favorite thing to do in reloading)

Cerrosafe cast of my 4570 chamber is about 2.115 so I stretch the cases out to that, fireform them with corn meal then trim to 2.105 after fire formed. Sometimes have to fire form and stretch more than once to get the case mouth squared.

Comparing accuracy at silhouette I don't see the difference on target between the unstretched brass and the stretched brass.

On target however it "seems" there may be a slight advantage to the stretched brass. Maybe not in your rifle.

So in commenting, I have had no case separations with brass trimmed to shorter than chamber length, knowing when you size a fired case you may observe that it is longer than when you measured it unsized.

Brass that is longer than chamber dimensions can be a problem.
Sometimes you get the chicken, and sometimes you get the feathers!
TJLeGault
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Joined: Fri Sep 12, 2014 9:21 pm

Re: Case Length

Post by TJLeGault »

Thanks for the reply
I was just concerned about a lead build up in the gap between the case and the step.If that's not a problem I don't want to buy 45-90 cases and cut them down.
firefighter1990
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Re: Case Length

Post by firefighter1990 »

I ventured down that same road with my 45-70. That particular rifle has only seen paper patched bullets of bore diameter. I experimented with different brands of brass and even got longer brass trimmed back to the 2.120" of that specific chamber. Lost a lot of sleep by over thinking it. I settled on fire-formed remington brass just because winchester is thinner and not as consistent; starline is thicker and harder. So kind of the middle ground but I never got paper rings from anything I tried and based on my shooting ability: I never could tell the difference on target between any brand and the few examples I trimmed long from 45-90 or basic brass. My rifle has the standard SAMMI spec grease groove chamber. My current fire-formed and unsized batch measures 2.095"
TJLeGault
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Re: Case Length

Post by TJLeGault »

Thanks for the info firefighter
One problem is I have a ton of Starline brass. I would hate to not use it. Sounds like I am worrying unnecessarily. I will never be using the rifle for serious long range competition or any competition. My max range around here is 600 yrd, but I only shoot at 100 to 200 yards.
firefighter1990
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Re: Case Length

Post by firefighter1990 »

Starline is good stuff once it's been annealed. I have shot my paper patch loads in standard brass at a local silhouette match and I think there's more variables in my shooting than what can be said about brass that is .030" short. My wife shoots greasers with starline brass in a standard 45-70 shiloh chamber and she's constantly besting my scores :oops:
TJLeGault
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Re: Case Length

Post by TJLeGault »

Good to hear I can keep using my Starine brass. I have not annealed it though I am doing to start doing that. Must be really neat to have a wife that shoots especially a BPCR.
Course one does not want to upset such a wife too much! LOL!
firefighter1990
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Re: Case Length

Post by firefighter1990 »

Ya especially when she's better than me! I'll take the high road and claim the better-spotter award
bruce m
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Re: Case Length

Post by bruce m »

whatever bullet you use, pp or gg, it will bump to fill any space before it starts to move on firing.
that includes the 0.030" section in front of the too short cases.
if your chamber is saami spec, it will have about a 12 degree transition between chamber and bore.
this is vastly more forgiving than the 45 degree transition used in smokeless chambers with jacketed bullets, and often transferred to black powder chambers in the mistaken belief that it is better.
the 45/70 was designed as a greaser chamber.
proper bore diameter pp chambers had transitions of 4 to 6 degrees.
bruce.
ventum est amicus meus
hepburnman
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Re: Case Length

Post by hepburnman »

If you have designed things this way, or you are lucky, it would be best to have a grease-groove showing right above the case-mouth. Upon firing, and bullet-bump up, the grease from this groove will be forced into any space ahead of the case mouth. The grease being forced into this area should help prevent lead shaving as the bullet transitions from case/chamber neck diameter to bore diameter. There would be a limit however to how short cases can be, from chamber length, for sufficient grease to be available to fill this space.
bobw
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Re: Case Length

Post by bobw »

Good thread topic. I all ways cringe when I hear some one tell new people to trim their new brass before they even have their rifle. Unbelievable to me, you don't know how long your chamber is until you have it in front of you to measure. bobw
bobw
hepburnman
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Re: Case Length

Post by hepburnman »

I've recently formed 40-65 cases from 45-70 cases. These were Starline which I first annealed. The forming die that I used is fairly close to chamber dimensions. Can anyone give me an idea of about how much the cases will shorten once they are fireformed? I am trying to leave the cases as long as possible with some up to 0.005" longer than chamber dimension. I will shoot these in a match. I am not concerned if the too long cases give me some degradation in accuracy as I want the fire-formed cases to be at, or near, chamber dimension once fired.

Thanks for the replies!
gunlaker
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Re: Case Length

Post by gunlaker »

Hepburnman, for my Shiloh .40-65 rifles I size Remington .45-70 brass in an RCBS FL die. I use the one designed for the Shiloh chamber.

I then trim them to about 2.113" and shoot them a couple of times. Then I trim them to final length. For slip fit in one of my rifles I use a length of 2.107". Anything much less and I get tiny wire rings of lead on the case mouth. On the second rifle I trim to 2.10" and it's fine.

From my notes, I'm getting around 0.006" reduction in length after the first firing.

Chris.
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Don McDowell
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Re: Case Length

Post by Don McDowell »

TJLeGault wrote: Thu Jan 23, 2020 10:09 pm The chamber length, measured with calipers of my Shiloh 45-70 Sharps is 2.125, measured from the breach to the step inside the chamber.
My Starline brass is 2.087 so its .038” short. All of my brass is short. The longest is Winchester but it still a bit short. My Speer reloading book even gives a trim to length (2.095) that is too short for my particular rifle as I measure it. My question is, should I buy 45-90 brass and cut it down to be 2.125? It seems to me I should but I wanted to hear what you guys think.
Thanks
My suggestion would be assuming your rifle is a "b" serial numbered gun to prep your starling cases, run them thru the size die, bell the case mouth, charge the case, seat the .458 diameter bullet to the point the driving band just kiss the lands, use just enough crimp to remove the flare on the case mouth, go shoot and have fun. Other than if you get some case mouth peening from cleaning in a tumbler that's probably the last time those cases will come in contact with any die other than the compression and seating dies.
If you get leading in the throat chances are pretty good that your fouling control or lube will be the cause.
AKA Donny Ray Rockslinger :?
TJLeGault
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Joined: Fri Sep 12, 2014 9:21 pm

Re: Case Length

Post by TJLeGault »

Thanks for the reply Don
My rifle is a "b" serial numbered gun.
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