Keyholing

3.6K Views
Last Post 24 February 2012

Standard Member

Lchoice posted this 01 August 2010

Hi everybody,

I am pretty new in the game of casting and shooting lead bullets and therefore struggle a little bit. When shooting my handgun I get good accuracy (3” groups with a red dot sight at 50 yards) for the first 10 shots. Then the bullets start to keyhole and the accuracy goes bad (12” or worse). After I clean the barrel the same thing happens again. I have no idea what is wrong and how to fix this.

I am shooting a Thompson Encore with a 12” 44 Mag barrel. The bullet is a Lyman 429421 powder 10gr Titegroup and a home made bullet lube 50% vaseline and 50% parrafin wax. The bullet speed should be close to 1300 ft/sec.

Unfortunately, I cannot seat the bullets to be close (.020") off the lands since Thompson cuts the throat very long.

Your comments and suggestions are greatly appreciated.

Attached Files

19 Comments

Order By: Standard | Newest | Votes

Standard Member

primersp posted this 01 August 2010

perharps the lube try to change

Attached Files

CBA Member

tturner53 posted this 01 August 2010

First, welcome to the forum. It sounds like you're getting leading in the bore to me. What is the diameter of your bullets? I'm shooting a .433” in my Ruger SBH. I'm not up to speed on TCs but with a revolver you need to seal the throat to prevent gas cutting and leading, which ruins accuracy. Also, what is your alloy? I think a lot of people go with a too hard alloy.

Attached Files

CBA Member

Duane Mellenbruch posted this 01 August 2010

Lchoice wrote: I am shooting a Thompson Encore with a 12” 44 Mag barrel. The bullet is a Lyman 429421 powder 10gr Titegroup and a home made bullet lube 50% vaseline and 50% parrafin wax. The bullet speed should be close to 1300 ft/sec. Are you starting with the MAX load given on the Hodgdon web site? Better to start low and work up til you either get accuracy. Duane

Attached Files

Standard Member

Lchoice posted this 01 August 2010

Thank you for your reply. What lube or lube recipe do you suggest?

Attached Files

Standard Member

Lchoice posted this 01 August 2010

Thank you for the welcome. The bullets are sized and have a diameter of .430. I am casting wheel weights without any soft lead stick on wheel weights in it. The bullets are not not quenched or hardened. I am not using gas checks.

Attached Files

Standard Member

Lchoice posted this 01 August 2010

I checked the hodgdon website and found that this is the max load and should push the bullet at 1423 ft/sec. This is a lot higher than expected. I will make some loads with a lesser powder charge and record the results.

Thank you all for the feedback so far.

Attached Files

CBA Member

tturner53 posted this 01 August 2010

Might try making a dummy round with an unsized bullet, if it chambers easily then that might be the diameter you need to go with. Bullet fit is more important than a few bhn in hardness, I don't see why the straight ww shouldn't work if the bullet fits the throat. Good luck and keep us posted.

Attached Files

Standard Member

corerf posted this 02 August 2010

Lchoice,

Have much experience with the barrel in question and that lube with that load, not going to hold up. Back off the load to about the anticipated 1100 fps range and use your lube with a fatter bullet. Your Encore throat will be as big as the groove diameter (corrected D. Mellenbruck thanks Duane) and likely 3 thou larger cause TC throat stink (deep enough to stick your middle finger out the muzzle and never touch the throat). Go with the fattest diameter bullet you can get in the chamber. I hate TC throats (factory that is).

Then work up. If you still have failed accuracy after 10 shots, the lube must change to a better lube. Your pushing aweful hard on that bullet for just straight WW with no quench and a taste small bullet.

I use a 310gr GC, White Label Lube carnuba red, sized to 432 (no sizing), and stuff it thru a 16.5 inch Encore 445SM barrel at 1900 fps with an enormous load of Win 680. I can shoot 100 rnds and eat out of the barrel. Bullets are quenched (I tried heat treat but is not needed) at casting.

You can shoot that hot but you need a GOOD lube that is designed for pressure and speed, plus a harder bullet that is larger in diameter (to suit the TC factory throat). Revolvers are better cut in the throat for a 430 bullet. I stress FAT/FAT/GOOD LUBE/FAT/FAT. I almost fell into a TC throat (the opening to hell) but for my wallet which stopped me from plumeting to my death! It looked like a bottomless pit, but theres no sign at the edge to warn you! But I love my TC frames! I digress.

This is my experience with the TC barrels, it is not LAW. These are my findings in my testing. Good luck.

Attached Files

CBA Member

Ken Campbell Iowa posted this 03 August 2010

Hi Corerf..."saved by my wallet.."

dang thats good he heh,thanks for the good week.

hey,how about some articles for Fouling Shot..

ken campbell,iowa

Attached Files

Standard Member

canalupo posted this 03 August 2010

I have been shooting cast lead 30 30 .308 with my TC 10 gr 2400. shifted gears to .311 tumble lube a little while ago. Sized to .311 fit in throat and give good to better accuracy 10 gr 2400. Very little leading because it is a slow mover. Lee lube seems to work for me

Good Luck

Bob D

Attached Files

Standard Member

Lchoice posted this 03 August 2010

Hi everybody,

I read all your replies and did the following: <>Changed from a Lyman 429421 sized bullet to a Lyman 429640 unsized bullet cast from wheel weights unquenched with a weight of 253 grains. Bullet diameter is .431 on the last band due to the Lee bullet seating die doing some sizing. The other 2 bands are .433.<>Changed from 10 to 8 grains of Titegroup powder.<>Changed the OAL to 1.85” and still far of the lands.<>Changed from home made bullet lube 50% parrafin and 50% vaseline to Lee Liquid Alox. Results after 20 rounds of shooting. <>Some crud in the fist 3” of the barrel.<>The rest of the barrel is almost perfectly clean.<>Smallest 5 shot group 2” largest 4” at 50 yards with a red dot scope no magnification.Overall I am very happy since I have now a starting base to work from. <>I will do some more work and try the following:<>Not clean the barrel and do some more shooting to see where the accuracy goes. <>Change back to the home made lube.<>Up the powder charge.<>Try a Lyman 429244 bullet.<*>Try the use of wheat fillers since 8 grains of Titegroup only fills the case 30%.It may take a while to get thru all of this but I want to find out what I can do with this Thompson Encore in 44 Mag.

Thank you for all the feedback and help so far.

Attached Files

Standard Member

Lchoice posted this 04 August 2010

I almost forgot one more very important thing. I am getting no more keyholes.

Attached Files

Standard Member

corerf posted this 04 August 2010

What was your final velocity, was it near your target vel? The results sound like my 357 mag load, LLA lube, Lee TL358-158 plain base, shooting IIRC 14gr of H-Univ with a firm crimp. I get 3/4 inch groups at 50 yds from a bench with Dan Wesson revolver. Some rounds have to be pressed into the cyl with some force the bullet is so fat (not my intention but it has yet to cause a problem or deter accuracy). I have tried various powder charges up and down, the leading goes away but so does accuracy. I am stuck with this bullet, on this charge. I would have to start over with a new bullet/powder combo to allow the possibility for an improvement. For me it has not been worth it. What I have is not perfect but sure shoots well. Accuracy is gone after 50 rounds, opens to 2-3 inches. But it's a moderate hunt load and I can't kill that many rabbits here in California in a day.

I get the same leading in the first 2 inch of the 8 inch barrel. It is tolerable and easily cleaned, plus it hunts like a champ. So you have a load that can be manipulated now. That is good news!

Good work.

Attached Files

Standard Member

Lchoice posted this 05 August 2010

I do not know what my final velocity is, but maybe I find out one day when I find somebody with a chronograph. With your handgun, you could have the cylinder reamed out by a gunsmith to get the fatter bullets in easier.

Attached Files

CBA Member

Dale53 posted this 05 August 2010

I am a BIG fan of conventional lube grooves and proven bullet lubes. NRA 50/50 Beeswax/Alox is proven and works quite well over a wide range of bullet speeds. The only complaint I have had is that it can melt in higher temperatures that I have been exposed to (contaminating the powder).

I changed to Lars White Label Carnauba Red some time ago simply because it has a higher melting point and works as well. It is also VERY reasonably priced.

Had a fellow club member that was having leading with Lee Liquid Alox. I talked him into trying Carnauba Red. His leading immediately disappeared.

Lchoice; You are making things a lot harder for yourself than you need to be. Titegroup is an excellent powder for target and standard loads. It is NOT the first choice for heavy magnum loads. You will be a lot better served in the .44 Magnum with H110 or Win 296 (same powder, different packaging) for full magnum loads. Using the Lyman 429421 as an example - I have shot thousands of these loads through several different .44 magnum revolvers with 23.0-24.0 grs of H110 with absolutely NO leading and excellent accuracy (along with taking a few deer). Maximum powder charge with that bullet is listed at 25.0 grs.

I shoot 23.0 grs for practice (easier on the revolver) and hunt with 24.0 grs.

My bullets are my cast bullets and are about the hardness of Lyman #2 bullet metal. My revolvers take .430” bullets (your TC may be happier with a fatter bullet as others have stated).

Titegroup will work very well with a WW+2% tin bullet (air cooled) at reduced charges (5.0-8.0 grs should work well) with the bullet sized to fit your chamber.

Use magnum primers with H110 or 296 (Winchester Large Pistol primers work well, also. Use standard primers with Titegroup.

Dale53

Attached Files

CBA Member

billglaze posted this 27 March 2011

I hope this isn't too far off subject, but I was having a severe leading problem in my Ruger .41 Mag. Load was 210 Gr. Lyman bullet, cast of WW, 10 gr. Unique. After 4-5 shots, I was lucky to hit the paper at 25 yds. Sent it back to Ruger, they changed the barrel; found it a little too rough. (Quick Service, too!) Leading diminshed to a little bit: ahead of the forcing cone, on the inside bottom only, accuracy much improved. Then, I got a S & W .41 Mag, brand new. (Yeah, I like the caliber!) Guess what? Leading to beat the band. Had to be something wrong somewhere. Now, I've used Unique powder for decades in .45 Colt, .45 ACP, .357 Mag. .38 Spl. and others with no problems. Powder was the last place I was looking. Then an article in the F.S. about a shooter having the same problem with a .41 Mag, and his friend said to “change powders! Go to H-110.” I figured, what the heck, a pound of powder's cost is worth spending 2 days off-and-on cleaning the S & W's barrel. I couldn't believe it!! The leading problem vanished. And I mean absolutely vanished! I can now shoot an unlimited amount through either gun, with no degradation of accuracy, and both barrels clean with just a patch and solvent! Lesson Learned: Everything is open to question. Sorry for the length of the posting, but had to tell the whole story to get sense of it.

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

Attached Files

Standard Member

corerf posted this 27 March 2011

billglaze,

I was doing what most casters do... using fast pistol powders instead of slow powders. Seems like 10g unique is working towards a fast moving bullet.

And so I leaded like a madman, even with tight fitting bullets.

Changed to slow pistol, mag powders, H4227, etc. With a full case, it leads lightly and I am doing j-bullet velocities. I can throttle back and eliminate leading completely if I choose to and accuracy is excellent/ I prefer a heavy load for hunting and flattening the trajectory though. When in doubt, slow down the powder a taste and you'll get the velocity increase but usually a pressure drop keeping a weak bullet happy in the bore.

Just my experiences, not a rule.

Attached Files

Standard Member

lmcollins posted this 23 February 2012

First: Remember that you are using a gas check bullet without the check, and are likely to get leading if you push it over lower speeds than you are trying to get. If you don't want to use gas checks get a nongas check mould like the Lyman 429421. You'll do better.

Second: We use faster powders to help “slug-up” bullet bases into the throat. You aren't going to do much of this without using a gas check... the bullet shank is too small in diameterto slug up. If you try a gas check, your lube is probably adequate.

The problem is a “gestalt” type thing. Get your whole act together. Sorry: should have siad your “HOLE” act together!