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Old April 27, 2012, 06:52 AM   #1
bkhann
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Problem 9mm keyhole

I am having a problem with my 9mm Bayau bullets (125 gr hard cast with a waxless coating). I am loading 5.3 gr of Power Pistol at col 1.125 resulting in 1100 fps.

These are excellent shooting rounds in my M&P pro 5.25" barreled pistol, but in both my 3.5" barreled pistols they keyhole (tumble). My FMJ rounds work perfectly in the 3.5" pistols, so it is definitely an incapatability of the Bayau rounds and the 3.5" barreled pistols.

Any suggestions as to what modifications I might do the the Bayau rounds to make them compatable in the 3.5" pistols ....or am I better off just to use fmj rounds in these pistols?
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Old April 27, 2012, 07:58 AM   #2
briandg
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first, IMO, just go to fmj. It's not that much more painful getting generic fmj than it is top quality hard cast, is it?

Why is it happening? You left out what kind of handgun it is. You don't say what the lead bullet diameter is.

here are some ideas, any of the below listed problems, maybe more than one, could be causing it.

Leading. needs larger diameter bullets. Short bullet shank stripping on rifling. excessive velocity stripping bullet on rifling (1,100 fps is a pretty hot 125 grain load.) Leades cut too long, not allowing grip, stripping rifling. useless lube. cheap, oversized barrels. Shallow rifling.

Plenty of possible problems, but the first thing to look at is your load; it obviously is the problem. Even if the barrel is flawed, your load is not functioning, so change it.

First step? maybe have a gunsmith measure the bores. check the bullet diameter while you are at it. Buy 100 hard bullets with real lubricant, not a coated bullet, in size increments of .356 and .357 to try, and REDUCE THE LOAD WHEN YOU TRY THEM! dump power pistol and stop running your lead at 1,100 fps. scrub both bores until there isn't even the slightest hint of lead or copper build up.

There are a few thoughts of mine. maybe one of them is the answer. whatever you do, approach this carefully. I just have this hunch that you are on the way towards a catastrophic failure.
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Old April 27, 2012, 08:26 AM   #3
Salmoneye
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Polygonal rifling?
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Old April 27, 2012, 08:33 AM   #4
briandg
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that would almost certainly do it with either small, or softer bullets. It won't swage the thing to really achieve spin.

another good possibility.
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Old April 27, 2012, 08:44 AM   #5
BDS-THR
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Keyholing will often occur when the bullet's bearing surface (part of bullet base that rides the rifling) can't get enough grip with the rifling and exit the muzzle without sufficient rotation to stabilize the bullet in flight so bullet starts to tumble.

For .356" sized Bayou bullets, .355" groove diameter barrels will work best and explains why the same load didn't keyhole out of M&P pro 5.25". If the 3.5" pistols' barrels are oversized (larger than .356") then it will explain why they tumbled, so I would slug the barrels first to determine the groove diameter.

If the barrels are oversized, you will probably need larger sized bullets and I do not believe Bayou sells larger sized bullets (you could call). If the barrels are not oversized, you could try upping the powder but my Lyman #49 lists 5.6 and 5.7 gr for 120 lead RN/CN bullets so you may not have much room for higher powder charges.

If you want to keep shooting the same bullet, you could try different powders. A faster burn rate powder like W231/HP-38 may bump the bullet base faster to provide better bullet-to-barrel fit.

As others asked, having the pistol make/model/barrel type would help.
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Old April 27, 2012, 09:38 AM   #6
bkhann
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A little more info:

Gun #1 (the one that is successfully shooting the Bayau bullets):
S&W M&P9 pro
-Barrel length: 5", Bore Diameter: .345-.346", Twist 1-18 RH

Gun #2 (Compact with keyhole)
S&W M&P9c
-Barrel Length: 3", Bore Diameter: .345-.346", Twist: 1-18 RH

Gun #3 (Compact with keyhole)
Kahr CW-9
-Barrel Length: 3.565", Bore Diameter: .3565, Twist: 1-10

All guns above have conventional (not polygonal) rifling

Bayau 9mm 125 gr RN bullets .356

In all the guns listed above, ther have been no signs of any barrel leading.

ALL ABOVE DIMENSIONS ARE PUBLISHED (NOT ACTUALLY MEASURED)
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Old April 27, 2012, 09:45 AM   #7
Salmoneye
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Forgive me, but I have never used a 'coated' bullet...

Are they .356" before coating, or is that with the coating?
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Old April 27, 2012, 10:04 AM   #8
briandg
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It's probably been coated like a .22 rimfire bullet with a very thin layer of hard wax. It should be the stated diameter before this lube is added.

Experts, with S&W using the new electrically cut rifling, without sharp corners, do you believe that this could cause the rifling to fail to grab the bullet?

Rounding off the land's corners will reduce the bearing surface at least a tiny bit, if the lands are identical in size to the standard square lands.

I have no idea if this could be a factor. I can't even guess.
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Old April 27, 2012, 10:42 AM   #9
bkhann
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The hard cast bullet is coated with a thin smooth coating. Some, like Black Bullets uses a moly-poly coating. Bayau uses a green proprietory coating. The coating acts as both a lubricant and sealer to the lead bullet. My experience with the 5" barrel M&Ppro9, as well as my friends full size Baretta, is that it shoots very accurately and leaves the gun clean with very little residue.

This recent experience with the shorter barrel guns is the only issue that I have had with these bullets.

My next step may be to try some other powders to see it the burn rate of the powder may be contributing to the problem. Power Pistol is a slower burning powder than a Titegroup. I have tested loads for each, so I may load up some titegroup loads and see if it makes any difference in the compact guns.

The other option is to use FMJ bullts in these guns. Either is doable...though I would prefer to be able to shoot all of my load options through all of my guns.
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Old April 27, 2012, 12:06 PM   #10
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I see posts like this so often I almost have a generic cut-n-paste reply.

Published data does nothing. Slug your barrels and get the ACTUAL dimensions.
You've overlooked the #1 rule of shooting lead. FIT is KING. If pistol #1 is doing good, I'd say you got lucky with a tight bore. #2 and #3 would likely do good with .357 or .358 bullets, and #1 would not suffer at all. Lead NEEDS a tight seal in the bore. 18bhn is not going to provide expansion in the bore to do that effectively. Oversizing a thousandth or two is standard.
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Old April 27, 2012, 12:50 PM   #11
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Longer bullets, that engage more rifling, might help, too.
Either a heavier, (thus longer), bullet of the same design, or
A different design, that is longer for a given weight, like a truncated cone bullet instead of round nose.
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Old April 27, 2012, 02:18 PM   #12
Don P
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Over crimping, or stretsh out your OAL to the max so it still chambers and still fits the magazine.
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Old April 27, 2012, 02:59 PM   #13
bfoosh006
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I would suggest you e-mail Bayou Bullets and ask for their suggestions.

E-mail - BayouBullets@yahoo.com or Phone - 225-324-4501.

Let us know what they say , if you do it. I'm curious.
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Old April 27, 2012, 04:28 PM   #14
Gerry
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Are you using a Lee FCD? Regardless of what you're using for crimping, make sure you're just taking down the bell you made to accept the bullet and no more.

Otherwise, just try another bullet since that's obviously not workin' for ya. I think .356" is a bit small for lead in a lot of modern 9mm guns and I prefer closer to 2-thousandth's over for good fit in all mine.

Last edited by Gerry; April 27, 2012 at 04:40 PM.
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Old April 27, 2012, 05:50 PM   #15
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No offense, but I'm going to venture a guess from some of these replies that a majority of the replies are NOT from reloaders with actual CASTING experience? Keep that in mind.
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Last edited by Rangefinder; April 27, 2012 at 08:32 PM.
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Old April 27, 2012, 07:36 PM   #16
bkhann
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I just loaded up 30 124 Bayau with 4.0 gr Titegroup and a COL of 1.125". This will yeild 1091 fps.

I'm going to take them to the range on Tuesday to see if they keyhole.
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