Shiloh Rifle Forums

jim,
i learned something with your B to B method thank you.and yes bore diameter pp bullet loads are different in that you want as much bullet in the rifling as possible, so the least in the case that allows the ammunition to function.
with swiss what has proved to work well is about 80 to 125 thou compression, so droptube the powder such that a wad on top of it is level with the top of the case and just adjust compression.
this makes designing a dual diameter bullet easy, as you know the depth it goes into the case, and add a little more to touch the rifling, and you have the length of the major diameter (fat part).
the fact that guys want to avoid the basics comes as no surprise.
smokeless guys in all disciplines and hunting do the same thing, and other guys tell them the answer, but they miss out the middle bit where you have to do the work.
so the whole thing is wasted, and the guy has to do the basics anyway as well.
the same with bullet moulds.
guys just keep buying multiple cheap shit moulds in the hope of lucking onto a magic one.
they end up spending more than if they just bought a ggod one in the first place based on measurement and nose profile for the job.
this is what keeps companies like lyman in business.
and they get to sell sizing dies as well and make more money from unsuspecting schmucks.
the old dead creedmoor guys just droptubed weighed charges into primed fireformed cases, finger or breech seated the bullets, and shot them well.
simple.
which brings to mind an issue to consider.
new rifle might mean new brass.
new brass will need necks expanded prior to loading, then you work out the B to B.
this allows ammunition to be fired and cases therefore to be fireformed.
after 3 shots the cases should be fireformed.
now is the time to establish a new B to B.
bruce.

Arnie, Douglas told you their 40s were 0.400 bore and 0.410 groove and that is what CPA offers? CPA's website says "Douglas XX Premium .40 caliber (.408")" and they told the OP "the bore is 0.4085". I suppose Douglas could have sloppy standards but somehow I doubt it. I'd take CPA's word for the .4085. But, as always, the bottom line is measure your rifle and go from there.

I just checked my CPA .40-65. It has the Douglas XX premium and it is a .400/.408. A 2" long .400 pin gage at the muzzle is snug with no wiggle the chamber cast is right on at .408 in the groove.

Kurt wrote: ↑Thu Jan 28, 2021 8:22 pm I just checked my CPA .40-65. It has the Douglas XX premium and it is a .400/.408. A 2" long .400 pin gage at the muzzle is snug with no wiggle the chamber cast is right on at .408 in the groove.

So is a.409 bullet too big in you experience?

That is something you have to see when you shoot it. .409" if it fits the fired case it will chamber if the bore riding portion fits the bore.

what kurt says.
further to that.
whatever the diameter of your case when obturated will be the diameter of your bullet when it starts to move.
this of course will not be the case with jacketed or so called hardcast or lyman no 2, but any alloy up to 12:1 or even 10:1 in hardness it will happen with black powder.
people look at bullet diameters pre firing and just assume they will be the same when fired.
same with nose profiles.
it just ain't so.
bruce.

Raven wrote: ↑Thu Jan 28, 2021 8:45 pm

Kurt wrote: ↑Thu Jan 28, 2021 8:22 pm I just checked my CPA .40-65. It has the Douglas XX premium and it is a .400/.408. A 2" long .400 pin gage at the muzzle is snug with no wiggle the chamber cast is right on at .408 in the groove.

So is a.409 bullet too big in you experience?

There is a issue that will show up with an oversized bullet, especially a GG bullet, and that is the base will get some finning, and that I don't know for sure if it is a problem unless the fins are longer on one side of the base I would think that as the bullet clears the muzzle and the long fins will get pushed by the gas causing some wobble or maybe even tumbling.
The oversized bullet diameter is effected more with the bore diameter than the groove depth. And if there is excess runout with the seated bullet you will get longer fins on one side of the base. I have seated bullets on purpose with excess runout to see the effects and the base will have a slant and the land cuts go farther up on one side of the ogive.
I have looked at some awful looking GG bullet bases cast soft as well with PP. But the PP usually will not get the cup base look as the soft GG.
Below are some PP bullets that show some starting of finning that were cast with different alloy hardness and paper thickness. This photo can be expanded for a closer look.

"Bore on the Douglas .40s is typically something like .4085”. We will slug the bore and make the groove diameter under the forearm after we get it fit. Lots of people like the Buffalo Arms “Money” bullets, look for .409” or .410” diameter.

Gail Shuttleworth"

From the hourses mouth if you will.

Thanks Gail.

Ravin,

I shot bullets two thousands over groove and three thousands under bore diameter and they shot just fine.
Don't get worked up in a lather worrying about a thousand. Just go out and shoot.

What Kurt said. My BA Kidwell Money bullet comes out of the mould at ~0.4072", and is very accurate in my Shiloh.

Clarence

Kurt wrote: ↑Fri Jan 29, 2021 4:05 pm Ravin,

I shot bullets two thousands over groove and three thousands under bore diameter and they shot just fine.
Don't get worked up in a lather worrying about a thousand. Just go out and shoot.

I agree Kurt. I just did not want to have some kind of leading or bullet shaving problem with a bullet a thousandth over bore if that is the case.
I am getting the brass and dies set up in anticipation of the rifle.

Looking forward to the shooting project to refine the loads for that rifle.

the bullet will be the size if the internal diameter of the fired case before it starts to move,
bruce.

the bullet will be the size if the internal diameter of the fired case before it starts to move.
gas cutting will give leading more than oversized bullets.
shaving oversized bullets is best avoided by changing the transition angle to a lower angle.
bruce.

I realize this thread is a bit old but thought my barrel specs might interest some. My CPA Douglas XX 40-65 barrel is stamped .4099" and that is what it is. I bought it 2nd hand so do not know if it was specifically ordered with .410" groove. It is a Shiloh chamber (2.100") with zero freebore.

What chamber design does CPA provide in 40-65 ?