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Discussion Starter #1
Checking some of my 45-70 brass today I was shocked to see how over length it was. I'm embarrassed to say just how much. Suffice it to say, way over length. So went to my 40 + year old Forester trimmer to trim. The mouth of the 45 case came right out to the very edge of the Forester cutter. This is a fairly new cutting shaft & is sharp but has refused to trim these cases. I have had no problem with it trimming smaller diameter case mouths. I went to my grinder & ground the case mouths down close & was finally able to use the Forester for the final little bit. This works but takes considerably longer. It appears I need to look into a different trimming process for this 45-70 brass. Recommended to trim back to 2.10 . Have any of you 45-70 loaders incountered any problems like this ? .
 

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Elk Whisperer (Super Moderator)
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I'll hafta check mine, but I don't load jacketed, just cast.

I should chuck one up in my 40+ year old Forster and see what happens.

RJ
 

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Discussion Starter #3
I load only cast myself . Have found it a hard go to trim 45-70 brass in my Forester.
 

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Elk Whisperer (Super Moderator)
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I've been gauging length by how my crimps turn out. Saturday I'll do some measuring and try to trim a couple. Hafta mine electricity tomorrow.

RJ
 
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If the cases fit in your rifle and chamber and you ONLY use those cases in your rifle, you are almost certainly just fine.
The max case length for ammunition to be safe in all firearms of that cartridge has to be equal or less than the length of the lede/rifling to the breech face. As long as there is room, the case is safe. It will NOT be safe for all .45-70 chambers, but it will be safe in yours. SAAMI shows chamber length to lede to be 2.1099" min and case length max to be 2.105", so you have 0.049" of "space."
I still find it hard to believe that straightwall cases can EVER expand, but I guess .45-70 is long enough so the case can stretch.
 

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I began checking some of my .45-70 brass today. I started with brand new Starline. All that I have checked so far are under length by a little, but there vary a very great amount. One would think that brand new factory brass would have tighter tolerances but I guess not. There is not more that maybe 5 thousands either way, so I may or may not trim them.
 

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Elk Whisperer (Super Moderator)
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I haven't done this, but, would annealing the case mouth help?
I tried it on a couple once (starline) but I couldn't tell where it "changed" anything. Just made the necks an ugly black color that so far hadn't gone away after 4-5 more reloads.

RJ
 

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Head space is off the rim and I have never found any improvement in accuracy from trimming cases to consistent length, so I trim only when necessary.
 

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Discussion Starter #11
Sounds interesting. Even my longest cases chamber easily. No problems of any kind. I could make a cast of the chamber. That would tell a lot...
 

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Elk Whisperer (Super Moderator)
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I measured a handful, maybe right, 45-70 cases, all Starline, that have all been fired at least four times. They all still measured (from Starline) 2.093-2.097, trim to is 2.095"

These were not resized, but "fresh fired".

I also found out the case head of a 45-70 will not fit in my Forster trimmer, nor do I have a collet that will fit them.

RJ
 

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Discussion Starter #13
I have a collet for 45-70 for my forester trimmer. It is a bit slower as the collet assembly has to be unscrewed & removed every time because the large rim of the 45-70 will not pass thru from the front . The case is then inserted from the rear of the collet housing & then tightened in place. Then unscrew the assembly to removed the trimmed case. Again & again. Slooooow but does work.
 

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Measuring cases before sizing is a waste of time. They grow in length when sized so you want to check and trim after sizing to make sure they are at the right length for your chamber.
Yes, straight cases do grow with use. It is true for 38 special, 357 Mag, 9mm, 40 caliber, 45 Colt and 45 ACP. Rather than checking the length of cases I just run them through my trimmer. I don't have to change adjustment because I use spools to set the trim length. My cases are always trimmed to the proper length. (I don't use the "trim to" length they are trimmed to chamber length -.002")
 

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Elk Whisperer (Super Moderator)
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1. Measuring cases before sizing is a waste of time. They grow in length when sized so you want to check and trim after sizing to make sure they are at the right length for your chamber.

2.Yes, straight cases do grow with use. It is true for 38 special, 357 Mag, 9mm, 40 caliber, 45 Colt and 45 ACP.

3. Rather than checking the length of cases I just run them through my trimmer. I don't have to change adjustment because I use spools to set the trim length. My cases are always trimmed to the proper length. (I don't use the "trim to" length they are trimmed to chamber length -.002")
1. That depends on
a. If you neck size with a collet. ✓

b. Measure a random sample of spent cartridges for length and using that data anneal and trim all of that "lot"✓

c. If you have multiple rifles in shooting the same cartridge using different loads/bullets. ✓

d. Use SAMMI trim to length and have "trim gauges" made from spent cases ✓

2. Yes, but at a much slower rate than bottle neck cases as they are usually of lower pressure. Ii find my 40 S&W got shorter when fired. As an aside, I've never trimmed any 44's or 357's and some of that brass is 50+ years old and usually splits before it needs trimmed anyway.

3. a. I have no reasonable way or desire to check chamber length. I'll stick with what's been working 😊

b. If one is working with a notorious case stretcher like, oh, say a 22-250 whose cases may grow .003-.004 each firing I'll still keep trimming them to trim to length when they get to say, .003 shy of SAMMI maxim length.

4. Anyways as we're discussing the 45-70, a not so notorious case stretcher and one that (for me) usually splits before it needs trimmed but hasn't done/needed either yet. Dom must shoot his a way more than me.

Dom, how much bigger is the rim than the bore of your Forster trimmer and does it look to you like a feller could "gone" it bigger and not mess up the "collet holder"

RJ
 

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Yes, straight cases do grow with use. It is true for 38 special, 357 Mag, 9mm, 40 caliber, 45 Colt and 45 ACP.
My experience with 45 Auto is they shorten about half a thousandth with each firing. I ran some bulk-purchase Winchester 45 Auto cases through 50 reloads one time (target loads with 200-grain H&G 68 type cast bullets and about 4 grains of Bullseye), and by the time I retired the ones that remained (many lost to mouth splits and as sacrifices to the range gods by then) they were uniformly about 0.025" shorter than they started out. Most of my straight cases don't really stretch much, either. QuickLoad's author, Hartmut Broemel, points out that most stretching occurs when a case sticks to the chamber wall and thr head is forced back into contact with the breech face without the rest of the case body moving back, and that this starts to happen when a load's peak pressures are in the vicinity of 30,000 psi. The exact number varies with the powder characteristics and the case and chamber geometry/ At lower pressures, the whole case slips in the chamber allowing the whole thing to back up in the chamber rather than stretching at the pressure ring area.

But that is not to say a straight case won't stretch if the pressures are high enough. M. L. McPherson pointed out that high pressure loads in his Marlin 1895s stretches the case. His loads not only reach a point where the pressure is high enough to clamp the case body to the chamber, but because the locking lug is at the rear of the bolt, the several inches of receiver steel between the locking lug and the barrel threads can be stretched by bolt thrust like a steel spring. As a result, the case is allowed to stretch by following the bolt face back into the stretch. He knows he's at that point when the round kicks the lever open and it won't close on the fired case again.

Dom,

In your shoes, I would pick up one of the inexpensive Lee case holder, cutter and "case gauge" tools and use a drill to run it. You need this $7 part set and this $6 part set.
 

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unclenick,
Are you measuring your brass after sizing?
If the cases are getting shorter, where is the brass going?
When fired, the case expands to the chamber and the mouth seals to the chamber wall to prevent gases from venting. When resized the brass is squeezed back to it's original diameter and the cartridge lengthens because the mouth is the only unsupported area of the case.
I have a set of spools that limit the travel of my trimmer so I don't have to make any adjustments. I put in the proper spool and trim. I run every round through the trimmer after sizing because it is faster than using calipers to check the length. If the cases got shorter then no trimming would occur after the first firing. In 50 years of reloading I have never experienced a fired case getting shorter. I do know that unsized cases are shorter than after sizing. I also experience trimming is performed on cases after multiple firing and sizing.
 

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Elk Whisperer (Super Moderator)
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While I can't answer for UncleNick and won't try because he's a waaaay smarter than me, what I did do was gather up three each head stamps ( new Starline and bazillion times reloaded *W-W and *RP) of 357 and 44 Mag and measured them for reference as I don't have any new 45-70 brass.

urlurl=IMG 20201009 105719007 — Postimages]


Let's start with .357 with a min-max of 1.280-1.290
New Starline - 1.280
Much used W-W - 1.269
Much used RP- 1.272

44 Magnum, min-max of 1.275 - 1.285
New Starline - 1.270
Much used W-W - 1.273
Much used RP - 1.273

All brass was picked at random from an unopened bag (Starline) or the corresponding coffee plastic into which empties get dumped and then measured with a Fowler 52-010-025 electronic caliper under the watchful eye of my expert and relentless mouser, table mooch and reloading helper Tuzo.



*Brass has been reloaded and fired at least ten times, possibly as many as twenty as I don't keep track of such things.

Where does the brass go? I suspect that in sizing straight wall cartridges it gets shoved back and stays there because on the up stroke of the die there is no "drag"?RJ

Are mine and UncleNick's the only cases of cases shrinking and not growing? I don't know but I suspect not.

Other than that, I have i have no explanation.

RJ
 

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The Hog Whisperer (Administrator)
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unclenick,
Are you measuring your brass after sizing?
If the cases are getting shorter, where is the brass going?
When fired, the case expands to the chamber and the mouth seals to the chamber wall to prevent gases from venting. When resized the brass is squeezed back to it's original diameter and the cartridge lengthens because the mouth is the only unsupported area of the case.
I have a set of spools that limit the travel of my trimmer so I don't have to make any adjustments. I put in the proper spool and trim. I run every round through the trimmer after sizing because it is faster than using calipers to check the length. If the cases got shorter then no trimming would occur after the first firing. In 50 years of reloading I have never experienced a fired case getting shorter. I do know that unsized cases are shorter than after sizing. I also experience trimming is performed on cases after multiple firing and sizing.
Ummm..... if you don't measure them, then how do you know that cases AREN'T getting shorter in .45 ACP loads?????
 

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When I run the cases through my trimmer short cases would not trim.
Most cases will trim, some do not. After firing a new case most cartridges do not trim but after the second firing most do trim. My trimmer is set longer than the "trim to" length suggested. Depending on the chamber length I have the trimmer set to trim from a couple of thousandths less to a few thousandths longer than SAAMI maximum length. Not all chambers are the same length so I made spools to limit trimming for my guns. I never trim to the "trim to" length, ithey are always longer than that dimension.
 
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