Stock Glock and Moly

[Apiarian]

I have been testing some moly bullets in my G22. I chronographed at the beginning and again at the end of a 50 round session. The ending fps average is 30fps higher that the start. I will do more testing and chrono work with 100 rounds.

Is this a normal rise in pressure with a stock Glock barrel? Do you think this is an issue?

[Jman]

With all else being equal, stock Glock barrels are at least 30 FPS faster than conventional rifled barrels in my experience. You may be seeing the results of inconsistent charges and or mixed head-stamp brass. Load your next run with matching brass. Check your charge weight more frequently.

If the bullets measure ~.401 and are a quality HARD CAST alloy and moly coat you should see NO leading and the resulting pressure increase

Is it an issue? Doubt it. This is of course if your are using good reloading techniques.

What does this load consist of? Make of brass, powder, bullet and primer. We might be able to shed more light on this.

Jim

[Apiarian]

I ran five 170gr (one string) and five 185gr (second string) at the beginning and recorded the ave velocity for each, then repeated at the end of the session. 3.9 to 4.0 grains solo 1000, Rem SPP. Most if not all the cases were federal. If there were any mixed in they were Winchester brass. The bullets are Precision. It is my understanding these are very soft.

I believe the barrel to have been clean at the start. I ran a bore snake through it and did a good quick eyeballing of the inside. I did an good examination and cleaning when I got home. I did get some leading in the barrel. I did the old vinegar, hydrogen-peroxide cleaning so the I know absolutely the next session I am starting clean.

[scottrebello]

I run exactly the same load (4.1) over 125 Bear Creek moly in two G 34s. I use mixed stamp and get about 30 FPS variation. Between normal powder dispensing variability +/- .1 gr and mixed stamps I think thats pretty good. Doesn't affect accuracy to my ability to test. Maybe off a mechanical rest but not me off a rest at 25 yards.

I have shot a thousand rounds in a day without cleaning, each gun, two shooters during a class. Did not see enough lead/moly buildup to get worried. 5 minutes with a lead cleaner in the bore and a few passes, patches come out clean.

[Jman]

It is my understanding these are very soft.

It is very strongly recommended that soft lead (moly coated or not) be used with a conventionally rifled barrel ONLY. Lone Wolf is a great value but needs the chamber reamed (opened up) slightly for reliably feeding .401 lead bullets. Send them 5 dummy rounds (no powder or primers) with your bullet seated and they will set you up nicely. Contact them. 208-437-0612 or email customerservice@lonewolfdist.com

Jim

[kevin c]

I have had the same changes with some moly bullets (Bear Creek) that the OP noticed. There was, for me, a real and consistent rise in velocity after shooting 100 or so rounds. It levelled off after that.

Leading from using cast bullets in Glock OEM bblsl, per a very good report in "The Glock in Competition", leads to increase pressure, which causes increased velocities. Continued leading from cast/swaged bullets, per this same report, is the cause of bbl failures as the pressures rise with continued shooting.

My experience was only with this brand of moly coated bullet. Other brands have different formulations and may not leave the deposits I am assuming that I get, and therefore there may not be a problem.

I stay with jacketed mostly. I clean my stock barrel if I shoot the moly in practice (no more than a couple hundred rounds). Interestingly enough, I have been told that the coated Precision bullet is "harder" than most. I'll test that brand for velocity rise if I decide to stay with moly in practice.

Edited June 13, 2009 by kevin c

[MoNsTeR]

sssaaaaaaaampliiiiiiiinnnnnnngggg diiiiiistrrriiiibbuuuuutiiiiiooonnnn

If you post the sample means, SDs, and sample sizes I can do the math, but even without seeing them I would bet $5 on randomness.

Edited June 14, 2009 by MoNsTeR

[Joe D]

Will the Glock barrels and lead bullets myth never end. I can't begin to tell you how many tens of thousands of lead and moly bullets I have shot through stock Glock barrels. Will the madness never end?????????????????

There are three major Glock internet myths/wives tales - lead bullets, firing out of battery and unsupported chambers.

[kevin c]

sssaaaaaaaampliiiiiiiinnnnnnngggg diiiiiistrrriiiibbuuuuutiiiiiooonnnn

If you post the sample means, SDs, and sample sizes I can do the math, but even without seeing them I would bet $5 on randomness.

Here's my data, which is from a couple years ago (turns out it was with Precision bullets, not BC, and my recollection wasn't quite what I actually recorded).

I did two tests a week apart, using the same G35 OEM barrel, and the same ammunition which was, per my reloading log, made from single lot components.

The load was 3.3 gr TiteGroup over a Precision 170 gr coated bullet, WSP primers, once fired RP brass and OAL of 1.100". Each string was shot from a cold barrel, and the first each day was from a clean barrel. A Pact Model I chrono was used at 10 ft, all shooting done at sea level on a cool day. All strings were of 10 consecutive shots.

The first test was before and after shooting 200 rounds of the same load.

1st string: 793 av 804 hi 784 lo 20 rng 8 SD

2nd string: 813 av 824 hi 795 lo 29 rng 10 SD

The 2nd test was before, after 100 rounds, after 200 rounds and then after dry brushing the bore with a phosphor bronze brush, about 20 passes.

1st string: 790 av 800 hi 780 lo 20 rng 6 SD

2nd string: 810 av 828 hi 795 lo 33 rng 11 SD

3rd string: 831 av 852 hi 815 lo 37 rng 12 SD

4th string: 817 av 826 hi 808 lo 23 rng 6 SD

The numbers looked convincing to me, but I'm no statistician. I'd welcome your analysis.

The tests I did were variants of Mark Passamaneck's work as described in Robin Taylor's book. He used lead, not moly/coated, and got much faster rises in velocities/pressures. He claimed that he could predictably make a Glock KB using soft lead bullets. Hard cast took quite a bit longer. I don't remember any mention of moly or coated bullets, which is why I did the tests for myself. I am NOT saying that moly will make a Glock blow, I am only relating what I found test wise, that was similar to but in a smaller degree compared to plain lead bullets.

I haven't ever had a Glock blow up on me, but that doesn't mean I don't weigh the evidence and opinions of people I know when there are concerns raised. My testing above made me think hard about lead use in a stock barrel, because I don't test hardness and don't clean the barrel often. Moly I'll use, but I remind myself to clean the barrel after each practice.

My Glocks will leave a striker pin mark on a live round when my springs are weak or if I have ammo that doesn't completely chamber for other reasons. Just because it hasn't caused an out of battery detonation yet doesn't mean I am going to ignore the risk when it makes itself evident.

As far as "unsupported" chambers go, well, there I agree that there's a bulge but not much risk unless there's some coexisting contributor (such as not being completely in battery, or weakened brass - otherwise, my main concern is ironing out the bulge.

eta: DDL was pretty good there, wasn't he?

Edited June 14, 2009 by kevin c

[Apiarian]

Thank you all for your input.

Kevin C., that is exactly the kind of data I was hoping for. The data looks consistent. I will continue to test in similar fashion.

I am committed to the moly bullet at this point. Worse case I get a lone wolf barrel. BUT, I am hoping the OEM will stabilize at 100 or do rounds. Here's hoping.

[MoNsTeR]

Welp, I would have lost that $5. Using a 2-sample unequal variance T-test against the two samples of your first set, we can say with 99.95% certainty that there is a non-random difference. Using the same method against each consecutive pair of samples from your second set (e.g. 1 vs. 2, 2 vs. 3, 3 vs. 4) the tests are again conclusive at 99.95%. Testing 2 vs. 4, we cannot conclude they are different, but that's likely what we would have guessed.

[kevin c]

Yeah, the numbers were unusually clean/consistent. I promise that I didn't fudge them .

I don't know why there was more of a rise after 200 rounds in the second test compared to the first.

Edited June 14, 2009 by kevin c

[michaels]

For one practice session, I loaded up 300 rounds of 9mm 124 grain lead (not moly coated, just plain lead) and ran them with about 2.9 - 3.1 grains of titegroup. These were shot out of a stock g17 with the factory barrel. I noticed that after 85-90 rounds, I was not getting good groups. I added maybe another 30 rounds and started to get flyers. I'm talking flyers of about 1 foot plus! Swapped barrels to an after market barrel and the groups went back down to normal and not one flyer. When I was done, looking down the stock barrel, it looked like a 25 cal barrel now. Took about 20 minutes of the acid cleaning to get it clean. I would guess that if I had continued with stock barrel, at some point soon, I would have caused severe damage to the barrel and probably my hand...

Tried it again a couple of days later with bear creek moly coated 135 grain bullets and shot 400 plus rounds out of the stock barrel, maybe a little bit of a lead or moly mark, cleaned it right out with a about 5 rounds of white box fmj.

not a scientific test, but in my gun, with the stock barrel, no more than a few lead bullets without moly. Just doesn't seem worth the chance of injury.

michaels

[Harmon]

ive seen immediate and severe lead buildup in my guns shooting moly coated lead in my factory barrel.

[Joe D]

I read some of Mark's (MarkCo) dribble over on Glock Talk years ago. What he had stated made zero sense to me. I knew shooters that had shot lead bullets through Glocks for years because no one had told them not to.

Sooooo that being said I decided to test some lead bullets myself. He had broad brushed all Glocks into the "Lead will blow up your Glock" category. I loaded up 500 125 gr Lead Valiant bullets with 3.5 grs of Titegroup. This load was to be my wife's practice load - 1060 fps.

After a couple of hundred rounds I pulled a Bore Snake through her Glock - no leading. 500 rounds no leading. At 1,000 rounds there was just a very slight trace of lead.

I realize there is very little common sense left in the world today. OTOH lead shooters have know for years that proper l bullet diameter, hardness and lube are key factors to successfully shooting lead through a Glock or any other gun.

BTW I forgot to mention my Glocks have not had a jacketed bullet through them in years. I have been using Bear Creek bullets with very good results. Yep, I still use lead bullets for practice.

Edited June 17, 2009 by Joe D

[kevin c]

It does seem to depend very much on the particulars of the bullet.

I'm glad that you've had no problems with lead in your Glocks, Joe. It seems that not everybody has had reassuring experiences, though.

[kevin c]

ive seen immediate and severe lead buildup in my guns shooting moly coated lead in my factory barrel.

Glocks, I assume?

[Harmon]

yes

[kildar]

I experienced lead and moly build up in my stock Glock barrel enough to make me concerned. It seems in this thread and others that this occurence is not universal. I can only assume, as with most barrels, that it's just the quirk of each individual barrel. Myself I still shoot moly coated bullets but use a Lonewolf barrel. I sleep better at night doing this.

[Apiarian]

I have found that Bear Creek bullets do not overly lead the bore. As far as the leading, the test was a success.

Now I have to work out feed issues. For the first time I am running into some rounds that do not pass the drop in the chamber test. I am also running into the nose-up feed issue. More sorting out to do. I will load some up longer and some shorter to see what is most reliable. I'm working with the 155gr BC in 40SW.

Edited June 25, 2009 by Apiarian

[kevin c]

Check what hits the paper.

At least in my 17 and 34's, the 147 BC's tumble.

Kevin

[Apiarian]

No tumble and accurate. Nice easy to see holes. I really like this bullet and powder combination. This is why I want to put the effort into it and get it to feed reliably.

Edited June 26, 2009 by Apiarian

[Joe D]

Kevin, what powder are you using? My wife shoots a 160 gr BC 9mm - no tumbles.

[kevin c]

Kevin, what powder are you using? My wife shoots a 160 gr BC 9mm - no tumbles.

TiteGroup

[Joe D]

I have not used TG in a couple of years. I used it very briefly with the 160 gr bullets. I don't recall any tumbling issues. I have since switched to Solo 1000 in 9mm.