Bore slugged .433 lands and .452 grooves, what size bullet and paper?

[cpileri]

Dear Sirs and Ma'ams,
When trying to load for a Model 71 Mauser, given that the bore slugged out to be .433 lands and .451 grooves, what size bullet shoudl i use?

The loaded ammo available from Buffalo Arms and grafs have .443 bullets, not paper patched.  Loose .443 projectiles are available.  So are .451-.452 diameter bullets.

I figure .433 bullets are too small to seal the bore, even with patching.
But, for safety and hopefully accuracy, would you go with .451's unpatched, or .443's patched with some paper that is 0.04-0.045 inches thick patched around it?

For informational purposes, the 71 Mauser original load was for a 380-ish grain paper-patched lead bullet in front of 77gr of black powder, pushing ~1450 fps.  I understand BP helps seal the bore by obturating the bullet.

My choices of powder can be either 77gr BP Equivalent of Pyrodex RS, or Triple SeVen or ~30grains of H-4198.

Any help appreciated!

Thanks,
C-

[Nobade]

How big a bullet is a nice snug slip fit in a fired case? Whatever size that is would be what I would try. Either a grease groove bullet that size, or a paper patched bullet patched to that size. The diameter of your PP slug will of course be determined by the paper you use.

I think you will be dissapointed with any of the powders you mention. That rifle will shoot best with real black powder, and you likely will be chasing your tail trying to use the others. Besides, that Pyrodex is some awful corrosive stuff and it's a shame to expose a nice old rifle to that.

[cpileri]

Dear Sir!
Thanks for being the first one to respond.  I am new at black powder.

Looks like I need to fire a case and see what the fired casemouth diameter is.  Slip fit is perfect as I did not buy the dies (way expensive) and have to use my fingers anyway.  I have 20 cartrsdges loaded with blackpowder from Buffalo Arms ready to go.  443-cal projectiles are on backorder, but I have a bunch of 451-2's around: lightweight, though. 

Interesting that real black powder will give best accuracy.  Is it because of the bullet obturation?

Also interesting, that my original reason for NOT using real BP was to not have to clean corrosive residue out of every nook and cranny of the rifle.  So Pyrodex is worse, in terms of corrosiveness?

Thanks!
C-

[Nobade]

Sounds like you are on the right track. And yes, Pyrodex is some terribly corrosive stuff. I have never had a gun rust after shooting black powder in it, but with Pyro it is important to clean it several times after shooting and pay attention to it afterward. I see a large number of pitted muzzle loader barrels in my shop and in almost every case the owner will admit to using it with Pyrodex. I won't touch the stuff any more. T7 is a little better in that regard, but still is far worse to work with than real black powder.

[crow_feather]

I have read that pyrodex fouling, when cleaned with ammonia will cause rusting.  I would imagine that some of these barrels are due to a smokeless powder cleaning  of a black powder rifle.

When using paper patch, remember that the powder used also determines bullet size.  Smokeless powder will not "bump up" the bullet diameter due to low initial pressure so the patched bullet has to be the diameter of the groove in order to fill the groves of the barrel.  Black powder will "bump up" the bullet and the fouling will fill the groves.  Bullets patched to bore diameter can be partially inserted into the bore, and upon firing, bump up to groove size if black powder is used. 

It is why I ended up stuck with two different diameter bullets for my Sharps.

CF

[cpileri]

Worse than with real black powder... so what in the world was the point of BP substitutes, then?

And using 2 bullet diameters is not what i had in mind at all.  i will try these BP loads, then try some RS or 777 (maybe); and see what works best.  I hear 4198 can be used: Hogdon or IMR?? at approx 30gr charge.  If after firinf/fireforming, the caseneck is larger than .443; i will paperpatch to make up the difference; or use a size-matched commercial bullet if i can.

After all that, whichever combo is the most accurate is the one I will stick with.

I read alot about lube cookies/wads to keep the fouling soft.  So I am pretty sure my load will be, from the top down:  bullet- lube cookie- filler- powder; where "lube cookie: is a 1/8 inch disk of ~60/40:beeswax/olive oil (maybe more beeswax if too soft) sandwiched between 2 disks of waxed paper.
optionally, i would insert stacked cardboard disks between the lube cookie and filler to take up any space in the caseneck (if using a light,short bullet).

I sure appreciate the replies.  Happy Easter!

C-
 

[cpileri]

I might get a chance to actually shoot this thing tomorrow.  i will post any info i get from the range if i do.
C-

[cpileri]

I did get out between rainstorms and tested the 71 Mauser.

It shoots about 18 inches high at 100m with the lowest sight leaf, which i understand is typical of these rifles which were zeroed at 300m.  Since the rear sight notch was small, I think a man-sized target past 300m would be challengeing.  The sights are graduated to 2000m for 'volley-fire' only, I'm sure.

Anyway, the fired cases showed some interesting details.  First, the shoulder was blown foward compared to the cases made from 348 brass by Buffalo Arms.  No cracks nor splits, just some unexpected fireforming.

The casemouth of fired cases measured:  ID: .448 and OD: .470.

So, given those measurements, and having .433 lands and .451 grooves; should I go with:

1. .443 bullet, .005 (man, that is THIN) paper patch; and use real Blackpowder to obturate to groove size?
or,
lets say i dont want to use real black.  are these viable options?
2. .448 total diameter patched bullet, some hornet nesting (*) to prevent gas blowby, and 30-35gr IMR-4198?  Hogdon 4198? Triple7?
or,
3. try to load a .451 bullet, swageing it down to fit in the casemouth; and hope it chambers (or shove really hard- j/k)

Something else?

(*) is there an alternative to hornet nest material for preventing 'blown' patches (admittedly a trick from the patched ball shooters)?  also, does 777/Pyrodex cause the same obturation as real blackpowder?

Thanks all for your expertise!
C-

[keith44]

Real black powder and pyrodex will reliably obutrate soft lead bullets.  I cannot speak for 777 or any of the others on the market (I prefer real black). 

I have yet to find a smokeless load that will cause obturation quickly enough to prevent blow-by.  Even my beloved black cannot always obturate that quickly.

As for the rest, I am trying to learn to patch bullets and cannot offer anything to the discussion.

Keith

[leadman]

I have a 71 Mauser that I use smokeless in. My bore measures .457" in the lands, but the neck in the chamber will only allow a .450" bullet to be loaded in the case.
I am using the Lyman .446" bullet lubed in a .450" die, then load just to the top of the base band. This inserts most of the bullet in the rifling. I use 21 grs of 2400 most of the time. Groups run about 3 to 4" at 100 yards with an occassional flyer. Leading is apparrent only if I shoot more than 8 to 10 rounds at a time without running a brush thru it.

I did build up the front sight with JB Weld to lower the impact at 100 yards.

Ross Seyfried wrote an article many years ago about the 43 Mauser. He used 4198 with a polyfil filler. I am going to try this soon.

I want to try paper patching, but due to hand surgery last week it will be awhile.

I have also thought about using the Lee 300gr .452" bullet with gas check sized to .450" just to see what it does.

[cpileri]

Hmmm... Sir, you dont happen to have a title and/or reprint of the Seyfried article, do you? I woudl be very interested in a copy!

C-

[bagdadjoe]

Worse than with real black powder... so what in the world was the point of BP substitutes, then?

Once they spend all that R&D money coming up with a "better mousetrap", they're sure going to sell it regardless.  I guess Pyro is safer to store...