Rechambering a 45-70 Farmingdale

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Stoneke
Posts: 26
Joined: Mon Apr 03, 2017 4:00 pm
Location: Klamath Falls, OR

Rechambering a 45-70 Farmingdale

Post by Stoneke » Mon Jan 31, 2022 4:37 pm

I am considering rechambering my 45-70 Farmingdale that has a freebore of about .355 inches. I prefer to shoot PPB and am having difficulty in getting good accuracy. Rechambering to 45-90 will leave a slight freebore of about .060 inches. Will this small freebore pose problems with either PPB or GG rounds, should I choose to use a variety of loads? Presently, I have been experimenting with PPB rounds of bore diameter or a few thousands under, seated well into the rifling. I have not tried any grove diameter PPB rounds. which will reduce my powder capacity. I am open to suggestions and thanks for the help.

bobw
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Joined: Tue Nov 23, 2004 12:52 pm

Re: Rechambering a 45-70 Farmingdale

Post by bobw » Tue Feb 01, 2022 8:08 am

The length of your freebore is typical of the older guns. It isn't as big a problem as it's more than likely overbored diameter. Patch some .450" ppb's to that overbored freebore diameter before you modify it. When you patch to bore in that kind of chamber you get poor results. Btdt. ..bobw
bobw

Stoneke
Posts: 26
Joined: Mon Apr 03, 2017 4:00 pm
Location: Klamath Falls, OR

Re: Rechambering a 45-70 Farmingdale

Post by Stoneke » Tue Feb 01, 2022 6:39 pm

I can only get three shots with the bore riding ppb. Heavy fouling at the muzzle with using a 3/16 grease cookie. Will need to go to a thicker cookie. Will try wiping after each shot. Have loaded a .458 ppb and reduced powder from 76 gr to 72 gr to provide a reasonable hgt column for the bullet and a thicker cookie. I will try a few options with groove diameter bullets before taking any steps to rechamber. I shot a 3 yr old Bison cow last week with a bore riding ppb, so presently energy power is not a great factor. Shot place behind the ear for and immediate kill. I am going to dwell on target accuracy for the time being and enjoy the Bison meat

semtav
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Location: Montana

Re: Rechambering a 45-70 Farmingdale

Post by semtav » Tue Feb 01, 2022 7:02 pm

What is the diameter of you freebore section?

Stoneke
Posts: 26
Joined: Mon Apr 03, 2017 4:00 pm
Location: Klamath Falls, OR

Re: Rechambering a 45-70 Farmingdale

Post by Stoneke » Tue Feb 01, 2022 7:18 pm

.459 -.460

semtav
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Location: Montana

Re: Rechambering a 45-70 Farmingdale

Post by semtav » Tue Feb 01, 2022 7:31 pm

Can you seat a bullet patched to .459-.460 in an unsized case?

semtav
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Location: Montana

Re: Rechambering a 45-70 Farmingdale

Post by semtav » Tue Feb 01, 2022 7:37 pm

I shot a .454 dia bullet patched to .460 in the Browning 45-90 with ,460 freebore for quite a while with excellent results, but if your chamber is too small and you can't shoot a bullet patched to freebore dia, you might be better rechambering to 2.6 with the chamber that matches the rifling. Too big or too little sucks.

77 sharps
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Location: N. CA

Re: Rechambering a 45-70 Farmingdale

Post by 77 sharps » Tue Feb 01, 2022 9:21 pm

What is the length of your barrel and what are you using for a over powder wad?

Mike

Stoneke
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Joined: Mon Apr 03, 2017 4:00 pm
Location: Klamath Falls, OR

Re: Rechambering a 45-70 Farmingdale

Post by Stoneke » Tue Feb 01, 2022 9:40 pm

30 inches and a milk carton wad.

mike herth
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Location: Buffalo, WY

Re: Rechambering a 45-70 Farmingdale

Post by mike herth » Wed Feb 02, 2022 6:58 am

I believe the simplest and most satisfying resolution to your issue is to have Shiloh rebarrel it to the caliber of your choice. Been there, done that, happy camper.

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Distant Thunder
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Location: NE Wisconsin

Re: Rechambering a 45-70 Farmingdale

Post by Distant Thunder » Wed Feb 02, 2022 10:50 am

Rebarrel it! Get what you want and need to have the best results.

While my Shiloh wasn't a Farmer and didn't have any chamber problems, it was one of many .45-70s and only had a 26 inch barrel so it spent all its time in the safe. I finally sent it to Shiloh and Kirk rebarrel it to a 17-twist .44-2 1/4 and it is now one of my favorites and it is the one I shoot the most. You may want to do this in a way that ends up where you want to be rather than end up with just another compromise. Just my opinion, YMMV.
Jim Kluskens
aka Distant Thunder

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