bullet diameter

[derskeeter]

New guy, please be patient.
Does a BPCR show preference for one diameter for all types of bullets? I am having a 45-90 built and believe the place to start looking for a bullet is with the diameter. If I try .458 and .459 bullets in say a 425 grain bullet and the rifle likes .459, then should I try other bullets and stay with the .459 diameter?

[country gent]

Some rifles do show a prefrence for a bullet dia. Knowing the throat, Lead and bore is a big help in determining a starting place for bullet dia. Talk to the people building your rifle and see if they can send you a print of the reamer ( Darwing) this will givea good idea of leade and throat length and dia. Normally BPCR bullets for use with black powder are softer 20-1 or 30-1 lead tin and will swell to fit bore when fired. Chamber will also have some bearing on bullet dia as some chambers are necked tight enough that a bullet .003-.004 oversize creates chambering issues. One thing consider is finding out before buying a mould. Buffalo arms and several others sell pre cast 20-1 lubed and sized bullets. Buy in several small batches diffrent styles dias wights and test them. 50 bullets will give a very good idea if the rifle likes them. Then when you find what works buy or have the mould made. In my 45-90 I use 500-550 grn bullets cast from 20-1 alloy or bore riding paper Patched in same wieght range. Dont get fixated on a certain bullet wieght,style, or alloy. Let the rifle tell you what is working.

[derskeeter]

Excellent information, thank you. Now I understand why the gunsmith was asking if I had a preference in chambers. He suggested minimum throat and very shallow lead. The rifle is a rolling block so we need to be careful about too tight of a neck to avoid chambering issues. It was reading the Buffalo Arms catalog that started this whole thing

[Gunlaker]

If the rifle has an oversized chamber or freebore that is larger than groove diameter it will likely prefer a larger diameter bullet. I have a rifle with a freebore that is a couple of thousands larger in diameter than the grooves. In this rifle, a bullet sized to fit the freebore diameter work far better than one sized to fit the grooves.

Ideally the reamer dimensions are a proper match for the bore/groove dimensions (and the gunsmith has the skills to do the job right). In that case a bullet at groove diameter will work very well.

Chris.

[Hednign]

Everything you need to know is mentioned above. I used to order a mold that was exactly true to the slugged diameter. However, Iv found that it is just as preferable to use a bullet that is just big enough to fit a fired case. Your chamber will not chamber a much bigger bullet anyways. I got an original 45-70 Peabody with a wowfully undersized chamber. The bore could take a .468 bullet, but the chamber only allows a .458 bullet. It doesn`t seem to matter as it shoots like a sob anyway... So I guess the bottom line is try and see what happens down range.

[country gent]

Hednign, That peabody's chamber may have been cut for a bore riding Paper Patched bullet as was the technology of the day. No throat just a leade from chamber mouth into rifling and The bullet was cast and wrapped to fit lightly snug into bore and obtrated up to fill bore on firing. Alot of the originals had tight chambers and oversized bores and bullets were soft to expand and seal fit the barrel on firing.

[kokomokid]

A 425 grain bullet for 45-90 must be for chickens and may not tell you much about the gun. LB

[derskeeter]

425 was just an example. However, I'm told it's a good hunting bullet because of the flat nose. Why would that bullet not tell me about the rifle? I understand to go long distances I would need a much heavier bullet.

[kokomokid]

I have tried a lot of light (440/450 gr) bullets for chickens for reduced recoil and they never shot as well as loads for the pig line. What is your bbl twist?

[derskeeter]

Twist is 1 in 18. I noticed in Black Powder Cartridge News that most 45-90's were using 535 to 560 gr bullets. But some were using 405's for short range work. I assume they are trying to control recoil.

[Hednign]

Hednign, That peabody's chamber may have been cut for a bore riding Paper Patched bullet as was the technology of the day. No throat just a leade from chamber mouth into rifling and The bullet was cast and wrapped to fit lightly snug into bore and obtrated up to fill bore on firing. Alot of the originals had tight chambers and oversized bores and bullets were soft to expand and seal fit the barrel on firing.

Oh yes, it is a paper patch Chamber.... I expressed myself a little unclear. My point is that you dont necessarily need a full diameter bullet to get great accuracy.