Slugged my rifle's bore, still uncertain as to correct diameter bullet

[Woodsman 22]

Hello guys;

I just got done slugging the bore of my new Miroku Winchester model 1892 in 44WCF cal. I used a "Meister bullets" bore slugging kit and followed the directions to the "T". The .427" slug came out completely engraved with rifling and without a lot of distortion. It miked .42710 to .42740" (my micrometer measures to millionths of an inch), and I was surprised at the variation from one spot to another on the slug. I moved up next to the .428" slug in the kit and now was getting readings closer to .428", but the driven end of the slug was more distorted. I finally tried the .429" slug, and you guessed it, I was getting readings consistently over .428" with some spots showing .429". I can't understand how this variation can happen, except maybe that the compressed lead on the larger slugs is expanding in places after falling out of the bore? It could very well be my measuring technique, I don't know, but this I do know- that .429" slug was HARD to drive through the bore (for the first couple of inches). It seems like the .427" slug went through with the least resistance while still showing complete engraving of the lands and grooves. Would you say that .427" bullets are the way to go? :veryconfu Also, I have bought some Winchester jacketed soft point bullets for this rifle and they measure .426.5" consistently. They are advertised as being for the 44-40 WCF, so I am assuming they are ok to reload with,but I wonder, will they rattle down the bore? .426" seems too small, but I am new to reloading and don't know if there is a difference in sizing between cast and jacketed bullets for a given bore diameter. All input is sincerely appreciated! :)

[runfiverun]

if a jaxketed bullet will grab the rifling it will be spun up to stability and powder blow by does nothing except lower velocity.

if you try that with cast it will strip the rifling and gas will blow by also it however will leave lead deposits behind from both the stripping and the cutting.
I would measure a case after firing a couple of the copper clad ones.
and see how much room you have in the case neck.
I would bet a 430 200gr boolit will shoot pretty well.
the Winchesters have lots of small rifling in their barrel, treat it like a marlin and it will do alright.
in my browning 92 and win 94 44 mags I use a 240 swc with a gas check at 430 to get the same results as I get in my rossi with a plain base at 430.
for my 44-40 I bump swage the 200 gr boolits to 430 and use a 45 colt seater die then bump the case mouth in the 44-40 seater die to take the flair out of the case.

[williamwaco]

+1

I would try .430.

Unless: If you happen to already own a .431 die, try it before you buy a new one.

[Woodsman 22]

Thanks for the relies, guys.

[missionary5155]

Howdy Woodsman22
I would fire that one round with a "J' thang and see what the fattest boolit you can fit into that fired case. Fill the throat with a lead boolit and everything will fall into place.
I have three 44/40 (44 WCF) 1892 SRC's and they all take boolits .432 or fatter. Grooves are .428 - .429 generally. These chambers were made to take BP fouling yet still be able to chamber the next round. But with smokeless there is no thick glob of BP residue to take up that extra space. So either the Boolit fills the gaps or the hot gasses blow by. Lead will easily slug down to any sensible barrel groove daimeter.
I would like to think the japs would have throated these new chambers to modern standards. But who really knows what Winchester ordered. What if the Miroku factory took measurements off a 1902 made carbine ? Fat throats and all.
Always do a complete measurement exam on every firearm before trying to shoot lead. Lead bolits are cheap to make but you have to do the homework to get them shooting right from the start.
Mike in Peru

[Woodsman 22]

Hi Missionary Mike;
Thanks for that information about the larger chambers to accommodate black powder fouling- I didn't think about that! But what do you mean by "I would fire that one round with a "J' thang ". Umm...what is a "J-thang"? (Duh)

[leadman]

Fire a factory or reloaded jacketed bullet and measure the inside of the case mouth after firing. This will give you the largest diameter cast bullet you can load in the chamber and still have it release safely when fired.
From your dimensions off the .429" slug I would try a .430" if it fits in the above fired case without expanding the case. You might get away with a .429" or not and have leading.
If you have a situation where the chamber is too small to take a bore size boolit you can load dacron or shotgun buffer in the case to protect the base if you are using a plain based boolit. This type loading comes with its own requirements as far as loading so ask if you need to do this.

[Woodsman 22]

Thanks Leadman! That is just the kind of info that I need. I have bought two hundred rounds of Magsafe 44 WCF cartridges and I'll fire a couple of those through the rifle to get the spent cases I need for this procedure.

[mdi]

Normally, when I slug a barrel I will use a slug at least .010" over suspected groove diameter. The barrel will "cut" the oversize amount at the muzzle (the "lead doughnut") and the slug will completely fill the bore as it is driven down the barrel. For my .44s I pour soft lead into a .44 case and remove it with an impact bullet puller. It comes out tapered so it's easy to start and plenty big to completely fill the bore...

[MtGun44]

This "largest boolit you can fire safely" is not correct. The case springs back so you
can safely load larger than the case mouth of a fired case, but not a LOT larger, maybe
.002 or .003.

The smaller slugs were not fully filling the grooves. "Too big" works fine, "too small" does
not work at all. So, I agree that you should start with .430 or .431.

Bill

[uscra112]

Load an unsized boolit in a primed case with a very small amount of powder. (I use half a grain of Red Dot). Find a safe place to fire this load with the muzzle up. This is of course guaranteed to stick the boolit in the bore, usually only a few inches in front of the chamber, which is exactly what you want it to do. Tap that back out, and you'll have a nice undistorted slug to measure.

[Woodsman 22]

Well guys, today I tried to drive a (well greased) .430" slug through the bore starting at the muzzle using the meister bullet slug kit. Unlike the other slugs, this one went in about 1/4" and then started mushrooming badly at the muzzle. The amount of force needed to drive it in even that far was alarming to say the least and I was afraid of damaging the crown of the barrel. So I drove the slug back out from the chamber end and no kidding, it looked like a toadstool. It measured close to .429" in most places, and I took a lot of measurements all the way round at the lands. So the end results were like this: the .427", .428" and .429" all went through the bore and engraved the rifling along the whole boolit. The .427" went through easiest, the . 428" was harder and the .429" was the hardest to drive through (and the driven end showed the most deformity). There were areas inside the barrel that the boolits passed through with less effort , and areas that required more elbow grease. It seems like the start and finish ends of the barrel showed the most resistance. So this is my conclusion: the best sizing dies would either be .428" or .429" and Lee does not make a sizing kit in .428". So I am waiting for a Lee sizing die in .429" to show up at Midway. What do you guys say? Is .429" the way to go? And by the way, I am thankful for all the info you guys have given me so far.
Oh, and by the way- I drove a Winchester copper clad soft point boolit through the bore (size .426") and I'll be darned if that sucker wasn't one of the hardest boolits to drive through that bore, except of course for the .430" slug which was impossible to hammer through. That part really has me baffled.

[Woodsman 22]

Oh, and this Miroku Winchester take-down rifle is probably the most beautiful gun I have ever owned. Really nice wood and perfect machining and finish, but that inconsistent barrel bore is a disappointment though.

[uscra112]

Yes, Miroku did a nice job. Got one in .32-20 that is a real peach. Everything except that synthetic varnish they finished the stock with. Hated that. Scraped it off and redid the wood in oil like it should be.

Not to worry about the looseness. Barrels often vary a few tenths without affecting the accuracy enough to matter. See what it does at the target.

My $0.02 worth is that, if you are going to buy only one sizer die, go to .430" Your cast bullet wants to be a thou or so bigger than the groove diameter, and it seems you have something like .429" grooves.

BTW for slugging from the muzzle, I've always had best results by using a round ball. Avoids that mushrooming problem. I take it that the kit you bought gave you cylinders?

An oldtimer's trick is to get a slightly undersize slug about halfway, then insert a rod from the opposite end, and hold it while you whack it 2-3 times with the first rod. This expands the slug to fit the grooves. Remove the second rod and drive the slug out.

I hope you have wrapped your rods with tape or shrink tubing to keep them centralized in the bore. An awful lot of damage can be done otherwise.

A jacketed bullet has far more friction than lead, even if it's undersized. Now you know!

Cheers !

Phil

[mdi]

The "mushrooming" is normal for a good oversized slug. The slug lead is way softer than your barrel and will not harm it. When you get the mushroom, continue to tap the slug into the barrel. When it seems like you might hit the muzzle with the hammer/mallet, switch to a brass punch to drive the slug into the barrel. Then a brass rod (or whatever you choose to use) can be used to safely drive the slug through. No need to do a half-way job, just use care ad you won't hurt your gun. I've used this method on all my guns that I shoot lead in (even my Ruger MkII); Moison-Nagant, SKS, Puma TC Contender, Taurus M85 and M86, Makarov 9mm, FMK 9mm (and a few others I ferget right now) and damaged none...

[Wayne Smith]

Do you know what the throat is? From your response #8 I thought you did. The throat is the area just ahead of the cartridge mouth, the largest diameter area of the barrel proper (not including the chamber). Don't worry about the diameter of the barrel - FILL THE THROAT. Lead compresses nicely inside a steel tube. Don't worry about that. That's why you are repeatedly told to get a size die of 431 or 432. You will also need either the RCBS or the Lyman expander die in order to get that big boolit into the cases.

[Woodsman 22]

"Do you know what the throat is? From your response #8 I thought you did. The throat is the area just ahead of the cartridge mouth, the largest diameter area of the barrel proper (not including the chamber)..."

Thanks Wayne, yes I do know what the throat of a barrel is, but I gewas just continuing with my attempts to slug the barrel the way the Meister kit instructions said to do it, just because I had the kit and slugs available to me. I will try filling the throat area with a larger sized slug once my hand recovers from surgery I just had. Thanks so much for the info!

[Woodsman 22]

"The slug lead is way softer than your barrel and will not harm it. When you get the mushroom, continue to tap the slug into the barrel. When it seems like you might hit the muzzle with the hammer/mallet, switch to a brass punch to drive the slug into the barrel."

Thanks for that information, mdi. I will continue with the bore slugging adventure once my hand is healed from the surgery I just had today.

[Woodsman 22]

"I take it that the kit you bought gave you cylinders? "

Yes sort of. They taper a bit at each end to make them easier to get into the bore. The "driving pins" they include in the kits are 5" long hardwood rods. I don't think those will do any damage to the bore.