Barrel Leading Question

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Tuscarora
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Barrel Leading Question

Post by Tuscarora »

First time Shiloh/BPCR owner guys. Set out today with a PRS rifle to get in some practice in the high winds and rain we are having. Just finished putting on the MVA sights on my brand new Shiloh 45/2.1, 30" barrel, and brought it along to get a rough zero. After the initial sight-in at 25yds, I did some quick figuring and dialed for a rock at 416 yards and had a great time killing that thing. All total, 15 rounds fired using a blow tube between shots. Nice grease ring at the muzzle. At home tonight I was amazed at the amount of fine lead slivers that I pushed out of the barrel with the second patch. Barrel cleaned up great though with only five patches. No remaining lead visible via a borescope. Accuracy while shooting that 6' rock dead downwind seemed quite acceptable to me for our first outing and the weather conditions. So the question is, why the leading?

The load was:
70gr's OE 2F
Lyman Postel 458132
WW Brass
CCI BR2 Primer
030 Walter's Wad
Powder compressed enough to allow bullet to seat to the first driving band putting the bullet .040-.050 off the lands.
Very light taper crimp

The bullets that I am shooting came from Montana Bullet Works. They are SPG lubed. The nice lady that I spoke to when ordering my bullets to be .450-.458 assured me that the nose section would be .450. No such luck! They are .452.

Anxious to hear some wisdom please!

By the way, I used to think I was shooting into the stratosphere when dialing 42MOA with 308 for 1200 yards years ago! :lol:
Eric Johanen
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Re: Barrel Leading Question

Post by Eric Johanen »

That has been my experience with Lyman molds. Quality control! She was probably quoting standard specs from Lyman. I have had more than 1 mold that is oversize in the nose and out of round. Very frustrating and I will not take a chance on Lyman again much better sources out here for a quality mold. ( This was fine when I had original 50-70 and 45-70 trapdoor Springfields as their bores were larger and could accomidate the larger noses bullets) Try to find a fellow who has a new to him original and make a donation,
gunlaker
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Re: Barrel Leading Question

Post by gunlaker »

That large nose will be a big part of the problem. Even ..450 is too large in my experience. .449" is what I prefer. I got Steve Brooks to make two moulds for me. One with a .449 nose and one with a .450 nose. The larger one shoots as well as the smaller one but definitely leaves lead in the bore.
If the alloy is really hard it can often be a problem too.

With that said, when shooting grease groove bullets you can often expect to find a little lead. Anything more than a sliver or two indicates something isn't quite right though.

Chris.
beltfed
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Re: Barrel Leading Question

Post by beltfed »

I agree possibly that 0.452 nose may be a problem.
But, It is possible that the body diameter of 0.458 is too small
and so you get a bit of blowby/therefore leading.
YOu might want to try a 0.459 or even 0.460 bullet body diameter.
beltfed/arnie
beltfed
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Re: Barrel Leading Question

Post by beltfed »

OH, another thing, you might try 0.060 LDPE wads, too

AND Paper Patch Bullets....!
beltfed/arnie
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Don McDowell
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Re: Barrel Leading Question

Post by Don McDowell »

The nose diameter is the problem most likely.
That can be over come by simply wiping a bit of lube or jojoba oil on the base of the nose to the ogive of the bullet.
AKA Donny Ray Rockslinger :?
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Lumpy Grits
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Re: Barrel Leading Question

Post by Lumpy Grits »

Never seen a .452 dia nose to hand seat in a Shiloh made bbl. :shock:
Gary
"Hav'n you along, is like loose'n two good men"
Eric Johanen
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Re: Barrel Leading Question

Post by Eric Johanen »

Right Lumpy. I like the nose at .448 or maybe a whisker larger. Must have nose clearance to clear any residual fouling left in the chamber after patching wet and dry to clean the barrel from shot to shot. Especially when blow tubing using greasers.
mdeland
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Re: Barrel Leading Question

Post by mdeland »

I don't believe nose lead is what is left in bores as recovered bullets I have seen don't show any or very slight nose contact with the bore in most cases other than when they set back a bit at the ogive. I also don't have much faith in supposed side ways nose slump which I think is happening at impact. I believe most leading comes from slight bullet base diameter changes in both groove and land. Usually the throat is the prime lead hook and also just past any constriction points up bore where it begins to open up again.
It should be pointed out that gas does not have to leak completely past a bullet shank to cause leading all it needs do is get past the base seal corner.
That is why the throat is a major leading point in most bores as the bullet base transitions the case mouth into the lead angle.
Tuscarora
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Re: Barrel Leading Question

Post by Tuscarora »

Gentlemen...this is good stuff reading your thoughts and I greatly appreciate it.

Lumpy, when the bore is clean, those loaded cartridges need only light pressure to fully chamber. Three slow breathes with a blow tube softened the fouling enough between shots that not much more pressure was needed.

Is it possible to "overdue" things with the blow tube and introduce too much moisture to the barrel fouling? What is a "normal" amount of toots on a blow tube?

And the next question now since beltfed brought it up...can I shoot PP in a Shiloh barrel chambered for greasers?
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Don McDowell
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Re: Barrel Leading Question

Post by Don McDowell »

The number of breaths from a blow tube to keep fouling from screwing with things depends entirely on temperature, humidity and how well hydrated you are when using the blow tube.
Yes you can shoot paper patch bullets very well from a standard shiloh chamber. .446 diameter 535 or 525 gr money bullet from a BACO mould cast from 16-1 and wrapped in seth cole 55Y. But you need to wipe between shots. Using a .444 diameter bullet in 8 lb paper and a lubed felt wad or grease cookie under the bullet you can shoot dirty for several rounds.
AKA Donny Ray Rockslinger :?
beltfed
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Re: Barrel Leading Question

Post by beltfed »

Indeed, you could shoot a 'patch to bore" bullet in your Shiloh GG chamber 45-2.1 as Don suggests
Of course you would need to taper crimp slightly so as to hold the bullet which will patch up to about 0.450 " or so

OTOH, you could go to a Dual Diameter bullet which would have a "Patch to Fire Formed case neck I.D." Base band
and a 'main body" that is "patch to bore ride diameter" to center up on the lands.
Now you can avoid the taper crimping of the brass and simply finger seat the bullets snugly in the fire formed cases.

Examples of two 45 cal Dual Diameter PP bullets in Buffalo Arms catalog for you to look at:
Jim# 453545E and Jim#455545E These bullets "saved" a couple guys after they had less than satisfying results with straight
"patch to bore" bullets

beltfed/arnie
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Don McDowell
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Re: Barrel Leading Question

Post by Don McDowell »

No crimp required, in fact crimping a patched bullet destroys accuracy.
AKA Donny Ray Rockslinger :?
bruce m
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Re: Barrel Leading Question

Post by bruce m »

45 degree transitions can give leading where 7 or 4, or even 12 degrees will not.
oversized noses and noses that bump into the rifling will also give leading.
bruce.
ventum est amicus meus
beltfed
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Re: Barrel Leading Question

Post by beltfed »

Before I got into Dual Diameter bullets, For my 40-72/gg chamber , I had a straight
patch to bore PP bullet cut. I Lightly taper crimped the fire formed cases Without
The PPed bullet installed--- just enough to have a snug slip fit to finger seat the bullets..
Definitely Not wanting to damage the paper on the bullets. This worked well, with good accuracy.
But, I like not having to do anything to my fire formed cases other than "verify" they case mouths
are true and round with a 2 step expanding plug.
beltfed/arnie
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