GP-100 lead issue.

Gents - I have a Ruger gp-100 stainless with a 6" barrel. Shooting lead bullets (Dardas 125 grain RNFPBB), with the blue Dardas lube. I am shooting 38 special loads, 3.5 grains of Titegroup.

After shooting 30 rounds, last weekend, I had quite a bit of lead in the barrel. I got it cleaned out using bronze wool (thanks to the fine people at Cast Boolits for that info).

At this point I am trying to determine the cause. Prior to shooting these, I had shot 25 rounds of 357 magnum loads with lead bullets (148 grain wadcutters over 3.0 grains of Titegroup), but did not look that close at the barrel for leading. Is it possible that the 357 loads may have leaded the barrel, and it just got worse as I shot the 38 special loads?

Since I have cleaned it out, I am thinking about running more of these rounds through it, checking for leading after each string of 6 rounds.

Is there anything else I should be looking for? Is the lube on the Dardas bullets adequate for this? Should I tumble lube as well? Does outside temperature have any effect on how well the lube works (it was about 10 degrees when I was shooting)?

I have also shot jacketed bullets out of this gun. Could this be an issue?

Sorry for all the rambling, but I just want to make sure I am headed down the correct path.

Thank you.

Tim

If those boolits are hard, you may need to bump up the load to get them to seal. Generally, you need soft boolits for target loads, or hard boolits that are VERY well matched to the chamber throats and bore.

I have a GP that leaded really bad. It turned out the bullets very hard alloy and were too small. I casted my own 358311 (sized to .359) from WW and some home brew lube and the leading disappeared 99%

1. Clean the barrel of all copper fouling. Sweets 7.62 or Montana X-treme Copper Killer are excellent products.
2. Slug the cylinder throats. You want a boolit .001" fatter than the largest throat. Others suggest throat diameter.
3. Store-bought boolits are generally too hard and their lube questionable.
4. Time to start start gathering casting equipment and supplies so you can cast boolits that work. Till then, expect mostly unsatisfactory results.

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3. Store-bought boolits are generally too hard and their lube questionable.

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This has been my experience as well. Since I started building my plinking loads with home cast boolits made of ACWW; properly sized, lubed with FWFL, leading in my GP-100 is a thing of the past.

Robert

If they go thru the cyl there to small & should be soft enuff to dent easily with the thumbnail .

I also find Titegroup to burn hotter than say CLAYS or UNIVERSAL, meaning boolits that did`nt lead will with Titegroup running the same speed over the chrony.

Wow - Thanks for all the responses. Looks like I have some work to do.

Thanks.

Tim

When I got the leading problem solved in my GP I fell in love withn that gun all over again.
Good luck, we are here to help.

I slugged the barrel, however, there are 5 lands and grooves, so I can't measure it with a set of mic's.

The bullet did not drop through the cylinder, so based on GP100man's response, it looks like they are not undersize.

The bullets do seem to be quite hard, Dardas specifies they are 16 bhn. Not sure if that is too hard or not.

I may try to tumble lube a small batch with LLA and see what the results are.

I will probably pick up a different powder as well. Looks like Universal may be a good powder to try, or is there something better to use with cast boolits?

Thanks.

Tim

i use clays and based the fit on the cylinder toom shoots great, just residue around the forcing cone area

I had the same problem with my 6" GP100 using Lee 158g rnfpbb boolits I water dropped. Even pusing them hard. Air cooled from that point and leading disappeared.

AJ

Try a good dose of 2400 under em & see what happens ,16 is gettin into rifle boolit range .

Alot of people compare UNIVERSAL to Unique but cleaner, also alot of HS-6 loaders .

Yeah the 5 groove thing is a pain . I formed a peice of soda can so I could pull it tite on the boolit then subtract 2x the thickness.

Precise ?? No , but close enuff for our purposes.

Thanks again for all the responses. I tumble lubed 30 bullets with LLA, and loaded them up. After shooting, there was a bit of lead residue at the forcing cone, and about 1/8" into the rifling. Again, this was using 3.5 grains of Titegroup.

Only took a couple passes with the bronze wool to clean it out. A great improvement over the previous session.

I think I will lube another batch of bullets, and try a different powder. I will also make sure the barrel is cleaned of any copper or lead fouling.

Thanks again.

Tim

I use 4.2 gr. of Titegroup with 125 gr. RNFP in 5 different guns with no leading. You may need to increase your powder charge.

Rond - My Hodgdon manual lists a max load in 38 special for 125 grain RNFP as 3.8 grains. I would not feel comfortable exceeding that. I will bump up these loads to the max to see what happens there.

I assume the higher load would tend to mush the base of the bullet into the grooves, preventing the burning powder from bypassing and eroding part of the bullet?

Thanks for your help.

Tim

X2 what GP said a good dose of 2400, or in my case HS 6 I was given some cast for my GP-100 . Unique loads leaded bad , they were sized right just hard boolits. I went to hs 6 and the leading stopped. They just needed a little more power.

I cannot find any published load data for 2400 or HS-6 with the 125 grain LRNFP bullets in the 38 special. Can you guys point me in the right direction?

Thanks.

Tim

I loaded 30 more rounds using Hodgdon Universal, 4.6 grains (just .1 grain below max). Had a little lead on the forcing cone after shooting these, but it cleaned up pretty easily. I think I am good to go with these bullets, but I think I may start casting my own.

Thanks for all the help.

Tim

i agree with so many responses here. contrary to popular belief, a little softer boolit and .002 over just plain works. i love my GP100 6in ss.

I should have read more carefully you need 38 spec. I run HS-6 in 357's/w 150 & 158 lymans
Lyman 49th has some loads for 120 cast in 38's

Shot about 50 rounds today with 4.6 grains of Universal, and am still getting some leading. But it is quite easy to clean up.

Based on the replies on this post, as well as other posts on this site, the hardness sounds like the main issue.

Based on my schedule right now, I won't be starting to cast for a while, but I did run across another thread that recommended Missouri Bullets, which have some softer bullets available.

The hardness of the bullets I am using now is listed as 16 BHN, while the Missouri Bullets are listed at 12 BHN. Would it be worth getting some from this company to try (I am assuming that 12 BHN would be the hardness range I would be looking for)? Have any of you guys tried their products?

Thanks again for all the help.

Tim

i use a 50-50 mix of pure lead and ww, after 250 rounds i had some lead apprent in the barrel just after the force cone. i patched with kroil let it sit for 10 mins ( i usually let it sit all day if its bad) then brushed it 5 times with nylon and then ran a lewis lead remover 2 times and it was shiney and perfect, i bet it was just blast residue from the cylinder gap.

If you have to use store-bought boolits, a BHN of 12 is better than one of sixteen.

Don't have the BHN numbers handy, but I use alloys of 50/50 or 2:1 wheel weights: lead.

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Originally Posted by TCoggins

Shot about 50 rounds today with 4.6 grains of Universal, and am still getting some leading. But it is quite easy to clean up.

Based on the replies on this post, as well as other posts on this site, the hardness sounds like the main issue.

Based on my schedule right now, I won't be starting to cast for a while, but I did run across another thread that recommended Missouri Bullets, which have some softer bullets available.

The hardness of the bullets I am using now is listed as 16 BHN, while the Missouri Bullets are listed at 12 BHN. Would it be worth getting some from this company to try (I am assuming that 12 BHN would be the hardness range I would be looking for)? Have any of you guys tried their products?

Thanks again for all the help.

Tim

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Penn Bullets make Cowboy Action bullets that are softer. You might try them as well. I find their bullets to be very accurate and get almost zero leading if loaded properly. I have also found if I run a brass brush through the barrel with Ballistol (probably any cleaner of lube would work) immediately after shooting for the day while the barrel is still warm the lead comes right out. If I wait until later I need to use the bronze wool.