Author Topic: Need HELP: Severe Leading in Model 686 (Read 603 times)

J.Solo · « **on:** June 27, 2004, 04:26:19 AM »

I have a S&W 4" Model 686, .357 Magnum and I'm shooting 158 grain SWC Hard Cast Lubricated Lead bullets from NBC Bullets out of Ohio. I'm experiencing severe leading at the front of cylinder, forcing cone and completely down the barrel. I'm using 6 grains of Unique as a load at about 1000 fps.

NBC Bullets measure .3590" dia.
All cylinder end holes measure .3575" dia.
Barrel Measures .3560" dia.

I have 2000 of these NBC bullets and would like to save them.

I also have a Lyman #450 Lubresizer press and I was thinking of getting a SWC Top Punch Die and a Sizing Die to resize all the bullets and all brands of future lead bullets. But I don't know what dimension to size to.

I don't know what Part Number and dimension of Sizing Die and Top Punch to buy. Based on the gun and bullet dimensions I have found, can anyone suggest what sizing die and Top Punch I should look for? Does anyone have a set up they would like to sell?

Thanks - J.Solo

jd45 · « **Reply #1 on:** June 27, 2004, 06:03:29 AM »

It seems to me that you are, in effect, "fire-swaging" the bullets as they pass from cylinder thru your barrel. 3 thou is a lot of down-sizing. Suggest you resize to .356-.357 max, if you can get your hands on the proper sizing components....check with the mfg'r of your setup. Good l
luck.jd45. P. S.---Lyman's # is 1-800-22-lyman---I'm sure if you explain to them what you're trying to do, they'll be able to help you.

ricciardelli · « **Reply #2 on:** June 27, 2004, 09:56:49 AM »

Swage your bullets down to .356, and reduce the velocity to less than 800 FPS.

J.Solo · « **Reply #3 on:** June 27, 2004, 11:14:37 AM »

I've posted this question on Graybeards, RUGER and S&W Forums. Most responses I'm getting say to decrease the load and size to .357-.378. I'll call Lyman tomorrow and explain the problem and see what size, sizing die and top punch would be correct. Anyone with a set up to sell please let me know before I order anything. Thanks - J.Solo

jd45 · « **Reply #4 on:** June 27, 2004, 02:17:20 PM »

The responses you're getting regarding sizing to .357-.358 are incorrect. Lyman's Pistol & Revolver Handbook says to size to groove diameter, which, in your case would be .356. Elmer Keith, in his book, "Sixguns", says you can safely go one thousandth of an inch over, to .357. That's why I suggested .356-.357 max. The more you have to squeeze that bullet down to groove diameter, the more likely you will experience leading. Simple. jd45.

J.Solo · « **Reply #5 on:** June 28, 2004, 06:12:37 AM »

I went on the NBC (National Bullet) Web Site and found that the 158 grain bullet I'm using has a Brinell Hardness of 18 (7% Antimony and 2% Tin mixture).

I also talked with a Lyman Rep. who confirred with their bulleticians and the most critical dimension I gave them were the cylinder exit holes of .3575".

Based on that they recomended a Sizing Die of .358. They said it was important that the bullet does not "rattle around" when leaving the cylinder and entering the barrel's forcing cone. the .0005" touch was enough to accomplish this.

I'm working with Lyman right now as to what Top Punch would fit the NBC bullets. Lyman's Top Punches are made for thier Molds so we have to find the best fit of Top Punch to NBC bullet.

I appreciate all the information so far. I've received a combinztion of information from all the Boards I've posted on that say:
Increase the FPS & decrease the FPS with the same powder, switch to a slower powder, try a different Lube, Lube should not effect it that much, size the bullet diameter down, leave the bullet diameter at .359".

My plan is to:
1. Re-size the bullets to .3580"
2. Use less Unique powder for lower FPS
3. Use more Unique powder for higher FPS
4. Try a slower powder.
5. Try VtVorhe (spelling) #110

Thanks for all the information to date. Keep it coming if anyone has anything else to share. - J.Solo

Blackhawk44 · « **Reply #6 on:** June 28, 2004, 12:56:32 PM »

Save time and trouble. The bullet size should be OK. The hard alloy and the bevel bases are compounding the problem. Take 50 bullets and drop them in a sandwich bag with a couple of squirts of Liquid Alox. Then add a tablespoon or so of rubbing alcohol. Seal and roll around in your hands until all are coated. Open bag and let dry for a day or two, then load. Should be much better. The hard alloy is keeping the bases from expanding to fill the throat and sealing gasses behind it. The bevel just makes it worse. Gas just blows past, melting a little of rear edges onto your throats and bore. Since the base isn't upsetting, its not compressing enought to squeeze the hard lube out of the groove to help. The alox should lube immediately so no lead adheres until the large diameter (but OK) bullet centers itself in the barrel throat. After this treatment, there should be no reason to re-size. Normally, a much softer bullet is better for non-magnum velocities.

J.Solo · « **Reply #7 on:** June 28, 2004, 07:48:02 PM »

Blackhawk 44:

So where do I get some Liquid Alox?

Please tell me I can get it at a Hardware or Auto Parts Store.

Thanks - J.Solo

J.Solo · « **Reply #8 on:** June 29, 2004, 04:47:52 AM »

I finally found my 1973 Lyman Cast Bullet Handbook and compared it to the information I have been using in the SPEER #13 Reloading Book.

The SPEER Manual lists 6 grains of Unique as the Max load = 1034 fps.

The Lyman Manual lists 8 grains of Unique as a Max load = 1400 fps.

I'm thinking that most Manufacture's loading manuals address their own, soft to semi hard lead bullets in their loading manuals while the Lyman manual addresses Hard Cast Lead bullets for their loads.

Without further experimenting it looks as though I've been loading Hard Lead Cast Bullets to Soft Lead Cast Bullet charges. This may be causing the leading I'm having, as the Hard Cast Bullet is moving too slow with the current powder charge.

My next step is to load the NBC bullets to 7.8-7.9 grains of unique and see if the leading stops.

J.Solo

Blackhawk44 · « **Reply #9 on:** June 29, 2004, 06:36:49 AM »

About any gun shop. Lee Liquid Alox. About $3 for enough to do 3-4000. Any of the mailorders like Midway, Mid South, http://www.fmreloading.com or http://www.natchezss.com.

Dave in WV · « **Reply #10 on:** June 29, 2004, 03:23:13 PM »

I had a 629 that was bad about leading. Take a jacketed .357 bullet and drop a bullet into the chmabers with the muzzle straight down. If the bullet drops through fairly easy the mouths to the chambers are too big and you will have to go to a larger diameter bullet. I fixed my problem with another revolver.