45/70 in the 45/90

[signut]

New to BPCR, have a question that I know will get answered here:can the 45/70 be fired safely in a rifle chambered in 45/90 ? I am thinking that the shorter brass might cause some chamber erosion if fed a steady diet of the 45/70. What is general thought on this?
Just started casting my own boolits after a 35 year hiatus. Using pure lead from a plumbers supply and pure tin from Rotometals. And they actually shoot pretty darned good....

[Don McDowell]

Yes you can do it. Accuracy will not be much after a few rounds of lead ammo due to the excessive throat leading, on account of that bullet having to jump 1/2 inch of freebore before it gets to the rifling. Chamber erosion is a real probability,but after how many rounds is the big question.
Keep it simple just buy the correct brass.

[NickSS]

I have fired many hundreds of rounds of 45-70 in a 45-90 chamber when I first got started shooting BPCR matches. It really happened by accident and I did not know about it until I sold the rifle to a friend of mine. I bought a Rolling block kit that was partially assembled. The guy I got it from told me that he had it chambered for 45-70. Well I put some elbo grease into it and came out with a nice rifle. I shot it for several years using 45-70 brass and mostly black powder loads. The rifle was a great shooting rifle but I sold it to a buddy who wanted to get started for what I had into it. Well at the time he was much more into playing with loads than I was and he found out that the chamber actually was a 45-90. Seeing as I was getting 1.5 moa with my loads I never worried about it as that was about as good as I can shoot. Well he bought some 45-90 brass and a postel bullet mold and reduced my 1.5 moa to about 1moa. I never experienced lead build up or chamber errosion in that rifle and fired over a thousand round through it.

[RMulhern]

Simple!

IT AIN'T THE THING TO DO!!

[John Boy]

can the 45/70 be fired safely in a rifle chambered in 45/90 ?
Signut, your question comes up frequently. Usually by folks just starting out with a 45 cal BPCR that they bought in 45-90.
The best answer was from Rick Mulhern - IT AIN'T THE THING TO DO!!
Just spend the extra cost for 45-90 brass and shoot the caliber that the rifle was chambered for ... Period!

[August]

Actually, with some of the heavy boolits, you can seat them way out in the 45-70 and get them pretty close to the lands. Some chamber measurements will verify this.

If your using a 500 grain+ boolit that is NOT a bore rider design, you ought to get it pretty close to the 45-90 length.

Actually, that's what most of us do with the 45-70 in order to get enough powder in it for 1000 yards, but we use a bore rider design in order to get the bullet down the bore before starting.

With the right boolit, it will work fine without a reduction in accuracy or increase in fouling -- assuming the leade on your rifle is not excessive.

[montana_charlie]

Actually, that's what most of us do with the 45-70 in order to get enough powder in it for 1000 yards, but we use a bore rider design in order to get the bullet down the bore before starting.
But, at no point in that chambering do you have a 0.30" length of bullet lying in a gap (between case mouth and chamber end) that is twenty thousandths larger in diameter than the bullet, itself.

At firing, a .460" bullet will bump up to .480" as it fills that empty space...and will be sheared back down to .460" as it passes the chamber step.

If that step is of low angle (like in some rolling blocks) the chamber end may not lead up. But, if it has the typical 45 degree angle, it probably will act as a lead trap.

CM

[Don McDowell]

Yessir that's exactly what happens in my Italian sharps with the chamber reamed to not quite 45-90 length, but much to long for 45-70. The thing will fill with lead in about 10 rounds when shooting 2.1 inch cases. Cut down 45-90 starline to 2.3 and I can shoot grease groove with no leading problems. Cut down norma 45 basic and those work wonderful for patched bullets as the case walls are then to thick to seat and chamber a grooved bullet.

[signut]

But, at no point in that chambering do you have a 0.30" length of bullet lying in a gap (between case mouth and chamber end) that is twenty thousandths larger in diameter than the bullet, itself.

At firing, a .460" bullet will bump up to .480" as it fills that empty space...and will be sheared back down to .460" as it passes the chamber step.

If that step is of low angle (like in some rolling blocks) the chamber end may not lead up. But, if it has the typical 45 degree angle, it probably will act as a lead trap.

CMThat is kind of what I was worried about. I have a 45/90 Shiloh, have some brass and more( Starline 45/90 ) on order . Think I'll just stick to the right brass and be done with it !. Thanks for all replies and info.

[John Boy]

Think I'll just stick to the right brass and be done with it !.
:drinks:

[bigted]

Yessir that's exactly what happens in my Italian sharps with the chamber reamed to not quite 45-90 length, but much to long for 45-70. The thing will fill with lead in about 10 rounds when shooting 2.1 inch cases. Cut down 45-90 starline to 2.3 and I can shoot grease groove with no leading problems. Cut down norma 45 basic and those work wonderful for patched bullets as the case walls are then to thick to seat and chamber a grooved bullet.



Don, what an exelent idea for pp cases that should hold onto the pp'ed boolit. i have some of the rcbs + inch brass that i will cut down one to see what the new neck dia would be for the 2.1 inch case. thanks for the suggestion. mybe not new idea :smile: but is to me

[Don McDowell]

Ted I'ld be interested to know how that comes out for you. I'm thinking about ordering some Jamison brass and cutting it down to the 2.3 length and see how that works also.

[bigted]

Don i went out and got ready to cut a couple down but thought better of it so i experimented with a lyman 457125 boolit i had laying around that meassured .4575 in diameter.

i took this boolit and slid it down the mouth of the open cases and to my astonishment ...it slid down to within 1/2 inch of the head. thinking i had a blown case i dug back into the box i keep my 120 cases in and selected another rcbs case and the very same thing happened. i next selected one of my bell cases and it also swallowed this boolit to within the same place. i dug out a new box of rcbs cases in basic length and it was still not fired so it was too small at the mouth to try but im betting that it would have done the same thing.

i guess i figured that the web area would have stretched up the case further then it does. so i will be leaving my long cases as they are becouse the only thing to be achieved with these is to make some basic cases into 2.1 length cases and ive got plenty of rem cases that work well for me in this.

next ill try to shove the 45-70 cases into my 45colt die to maybe get the tightness for the pp boolits i aim to try someday. i want them to hold the boolit tight enough to use in hunting without them falling out while walking.

if you have different results id like to hear about them as well

[Don McDowell]

Ted, that's interesting thanks for the information. Will let you know when I get ahold of some of that Jamison brass how that goes.
I trim those cases down with my Lee 45-70 case trimmer chucked up in my drill press with the stop on the press set to give the length I want.
What I've found is that with my Lyman 45-70 dies if I full length resize Remington or Winchester cases that without doing anything else to the case, my patched bullets stay fairly tight. I have ran loaded 45-70 patched rounds into my 45 colt size die (rcbs about 40 years old) until you could just feel tension and those have held solid enough for hunting.

[texasmac]

Back to the original question. Click on the following link for my "long-winded" response.

http://www.texas-mac.com/Shooting_Short_Case_Cartridges_in_BPCRs_Myths_and_ Facts.html

Wayne