Getting my 45-70 out of the gun cabinet.

[martinibelgian]

Last weekend, I decided to give my 45-70 another try, this time with GG bullets. Lately, results with PP bullets have been bit lacklustre, I've been blaming this on the barrel nog being in the best of conditions.
So I decided to try it out with a GG load. To keep a long story short, the barrel on this rifle is .462 groove, and I had a CBE mould lying around that had just that diameter. A GG bullet, kinda like the Lyman 457125, except a bit 'fatter'.
So I tried it out with following load:
WW cases, Federal LR primer
78grs of Swiss FFg (no.3)
Card overpowder wad
520gr. CBE 'govt.' bullet, lubed with beeswax, lard and peanut oil mixture

Below the target shot at 200m, prone, sling only. not too unhappy for an untested load, new bullet.


Might need some tweaking, but looks promising to me...

[semtav]

Looks promising !!
I'm just headed the other way with a 45-70. Trying to get it to shoot PP loads.

Quit snowing so I tried a 10 shot group that turned into a 7 shot group
2 moa horizontal by 1.5 moa vertical
hope I can improve on that but with iron sights, might be as good as it gets with the current shooter

[martinibelgian]

Fwiw, I also tried the Polish Zloty Stok powder, 71.5 hrs of it, with the same bullet. A similar group, but 13 minutes lower.... That's a lot at 200m

[Gamerancher]

Just out of interest, is that barrel of Italian manufacture?
Just curious as I used to have an Italian Sharps replica that had that exact same dimension, I also know of two others down here that have the same .
I had Steve Brooks make me a mold that cast at .463" and 530gr, 4 GG's. That shot very well for me.
I'm sure he'd still have that design on hand if asked.

[martinibelgian]

No, US manufacture by Ron Snover, Metford segmental rifling. Kinda a not-so-nice surprise when I found out. I just might go for a new mould if this keeps showing promise, do you have a pic or drawing of your bullet?

[Gamerancher]

Sorry, I don't. Sold the rifle and mould together when I got my Shiloh, ( made sense ), haven't seen the fellow since.
I used Steve's design page on his website, basically a hybrid Postell/Creedmoor with 4 GG's. Steve may still have it on file? You have my permission to use it if it's needed. ( Actually now that I think about it, it was very similar to the Paul Jones .459, 530 gr bullet I use in my U.S residing .45-70.)
With 62.5 grains of 2F Swiss, a white card wad, L.R magnum primer and me doing my bit, it would hold 5" at Turkeys. ( 385m ) I believe it could be made to shoot better, I was a total newcomer to BPCR at the time.

[BFD]

No, US manufacture by Ron Snover, Metford segmental rifling. Kinda a not-so-nice surprise when I found out. I just might go for a new mould if this keeps showing promise, do you have a pic or drawing of your bullet?

A Snover barrel is not so nice? I'd love to have one. Always wanted to try Metford rifling.

[martinibelgian]

It isn't when you asked for a standard .450/458 barrel, but instead get a .462 groove dia. Chamber reamers are the 1st issue, followed by bullet diameter.
At 1st it shot (almost) groove dia. PP very well, but for some reason accuracy diminished after the 1st few shots, whatever I tried. Even lots of cleaning didn't help.
But this GG load seems to show promise.

[mdeland]

I'd suggest getting a set of plug gauges and figure out if the barrel needs a good lap Job. It can make all the difference if you have some inconsistent bore diameters.
Shooting alone can smooth a bore up but it won't change a tight or wide spot any.

[martinibelgian]

No inconsistent bore diameter, just too large . Which is why I'm using the .462 bullet. I might give bore-dia. PP a try too, who knows?

[mdeland]

You will really never know how consistent your bore diameters are without a lap slug or plug gauge, especially with vintage military rifles. It is quite an eye opener for sure.

[77 sharps]

Does that barrel have gain twist, or more accurately a noticeable increase in twist rate 2/3 to 3/4 of the way down the barrel? A Metford barrel is likely to not cut the patch into strips so the patch will have to unwrap instead of blowing into pieces. The twist rate change tears the paper into small pieces so the patch blows off quickly. My experience with Metford barrels is limited, but I noticed the twist change in the barrels. If the patches are not clearing the bullet quickly, this might explain the GG bullets shooting well while the PP bullets are not.

[martinibelgian]

Well, in the past the pp bullets did shot quite well....

[77 sharps]

I was thinking that any surfaces in the barrel that were cutting the patch might polish out quickly with paper patches. Inspecting your patch fragments will tell. Metford thought that the twist change was necessary for best accuracy from what I have read. Just a thought, I am likely wrong.

[mdeland]

Metford I have read used segmented rifling but not sure it was in a gain twist. That is the lands and grooves were intersecting segments of a circle( think polygonal rifling) and that this was what consistently broke up the paper patch but I think the pitch was even. No?
Gain twist ought to achieve the same result I would think with standard profile lands and grooves.