I am trying to check the regulation on a 450BPE. Was planning to use Woodleigh 350 grain 458 softs. Per my usual practice, slugged the bore from both ends. Came out at .465 near the chamber and .456 at the muzzles. I double checked, so I don't think this is a measurement mistake. Good strong clean rifling. So now what?

Russ,

Not enough experience with BPE to be definite. Not sure that two thou at the muzzle will matter at BPE pressures there. But, if the gun's maker still exists, might enquire there.

Hopefully 400 Nitro will reply to this thread as he has a wealth of pertinent knowledge/experience.

Regards, Tim

My 577 2 3/4" BPE Has .002 constriction at the muzzles. Shoots fine.

Dave

Forgot to add, I shoot paper patched cast bullets. Dave

The obvious solution is a paper-patched lead bullet, which is what .450 BPE rifles were designed for. The .450 BPE was never loaded with jacketed bullets, only paper-patched lead. The .450 Nitro for Black was never loaded with jacketed bullets either, only metal-based (gas check) lead. Conversely, reflecting the completely different intended uses and pressures, and to provide a failsafe, at-a-glance method to avoid mixing the two, .450 Nitro Express was loaded with Cupro-Nickel jacketed bullets only.

A few weeks ago, I was looking over a .500 BPE hammergun from 1892 with original steel barrels. In the case was a letter from the maker (Holland) dated 1964 in response to a request for historical data. The letter provided the data, then volunteered a stern warning NOT to fire jacketed bullets in it, saying that the rifle was designed for lead bullets, and that jacketed bullets could possibly damage it.

I dunno. To this day, among the rest of their proof marks, the Belgian proof houses STILL stamp each rifle with the type of bullet proved for. "Lead Bullet" (balle plomb) is marked "B. Plomb". "Jacketed Bullet" (balle blindee) is marked "B. Blindee".

Personally, I wouldn't use a jacketed bullet in a BPE rifle.

The rifle is by H&H and for some reason I am not getting any answers to emails addressed to those gents.

I also know of a Purdey in the same caliber with tapered bores. So this is not an anomaly. I suspect there are quite a few BPEs out there with tapered bores and the owners don't know it. If your rifle won't hold a group, you may want to check. Shooting an undersized bullet (based on a a pass through slug) is not conducive to accuracy.

In researching this, I discovered that all Martini Henry 577-450 bores are tapered...as much as 15 thou of taper in the bore. These rifles were made to shoot paper patched bullets, sized to the lands of the largest portion of the bore, so that is what I am going to try with the H&H. The paper will take it out to groove dia. I am very interested to see what happens to the paper!

I am not sure what the theory behind this is/was. Perhaps the progressive swaging of the bullet ensures that it seals perfectly even as the paper wears. Obviously, this won't work too well with a jacketed bullet which is much harder, or a naked GG bullet, as the bullet will lead the bore unless it is very hard in which case you are back to the jacketed problem. Boring and rifling a tapered bore has to be much more tricky than a level bore, so there must be some advantage to this.

I am also curious about vintage ammo in this caliber. Were over powder wads used? Does anyone have any ancient paper patched 450BPE ammo? I would be very curious to know the overall bullet dia as well as the lead core dia.

Tapered bore or not ,the BP day's barrels were made of soft steels not like modern barrels.Jacketed bullets have no place in these barrels as there will be significant wear !!

Almost all Alex Henry double rifles (black powder) have tapered bores. I agree that this was due to paper patching as the bullet is squeezed down the bore to seal tight so no blowby. A Holland Royal Hammerless .450 BPE with an original mold that I have was made to shoot the Holland grooved lead bullet, no patching and no gas check.