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Comp Erosion


tyler2you

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After a match on Saturday where I was having trouble hitting steel with my Open Gun, I decided to take it to the range to see if anything was wrong. I started by shooting some groups and had trouble keeping hits inside an 8 inch circle at 20 yards. I took a look at the comp and noticed I was suddenly getting baffle strikes on the right side of my comp. Same bullet, same load, nothing changed, so I decided to clean it all up and make sure it wasn't cracked. No cracks, but I noticed I'm getting quite a bit of erosion on the 2nd and 3rd ports.

Anybody have this kind of erosion? My load is a 115 gr PD JHP and 8.8 gr. of HS-6. Comp is Titanium.

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I have heard from another shooter with the same comp that it needed to be retapped with a bull barrel tap to correct the threads. The threads are cnc milled, and in his case the threads were not milled deep enough to allow the comp to thread on the barrel correctly. I don't think he tried to cool the barrel in the freezer (to shrink it) and heat the comp in the thread area (to expand it) before fitting. In any event it appears to be out of alignment so it will need reaming to correct. Is this the same Tyler that shot Brocks Gap Saturday?

Just a FYI I am not bashing this comp in anyway, I think it is a great design and it is obvious the amount of work and attention to detail he put into it. I do machining on slides and sometimes you make mistakes,or sometimes you have problems caused by worn tools, it is just a part of being in this business.

Edited by MrPostman
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Trent1k1: Not copper--the metal is eroded.

MrPostman: Yep, that's me. Gun was shooting great at 10 yards, but when I tried to verify my zero at 20, it was all over the place. I blew 30 rounds doing the CMore shuffle before I realized I was getting baffle strikes. Weird thing is that I had just zeroed the gun prior to Area 6 and it was shooting nice 1 inch groups at that distance. I haven't changed anything and all of sudden I'm getting strikes.

kcd19: I don't think it's a thread issue in this particular case as the gun was shooting perfectly 3 weeks ago.

I can fix the issue with the baffle strikes, but am concerned about the erosion as I've only got around 4 thousand rounds on the gun.

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Just a hunch but maybe the slide is hitting the comp when the gun returns to battery. This would cause the comp to shift slightly and cause the strikes. When fitting a comp you want enough space in between the comp and slide to keep them from touching when the gun returns to battery. The barrel should only touch the slide at the breech face when returning to battery.

Just test it by racking the slide by hand and letting it slowly go back into battery and take note of where it touches.

Edited by MrPostman
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Looks like build up to me and not erosion. Clean the comp out. Check that it is still tight and not loose or rocking. Make sure all proper clearances still exist. Check slide to comp and barrel plug to comp. Ream the comp to touch it up and remove any last build up or high spots. Go shoot.

Cleaning out my comp and touching it up by hand with a reamer is standard maintenance for me now. I keep the comp oiled which helps it self clean and loosens buildup.

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Erosion.

I had a Bedell Ti comp that eroded after so many rounds using HS6 exclusively.

Both my open guns with steel Brazos comp is showing erosion also.

I've heard HS6 is notorious for eroding comps.

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Just a hunch but maybe the slide is hitting the comp when the gun returns to battery. This would cause the comp to shift slightly and cause the strikes. When fitting a comp you want enough space in between the comp and slide to keep them from touching when the gun returns to battery. The barrel should only touch the slide at the breech face when returning to battery.

Just test it by racking the slide by hand and letting it slowly go back into battery and take note of where it touches.

How much clearance do you want between the comp and slide, and then is there a point of to much clearance between them.

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Just a hunch but maybe the slide is hitting the comp when the gun returns to battery.

How much clearance do you want between the comp and slide, and then is there a point of to much clearance between them.

Haven't had any issues with .005" to .007" with Bedell Titanium comps. More doesn't really cause any problems,

the gap just becomes more noticeable.

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Well you want at least .003" bare minimum and maybe .010" at most. Any larger than .010 and the gap is noticeable. You could however cut it back .050" and it would still be accurate but look ugly with the gap.

FYI The Trubor does not have this issue because it is cut from a single piece of barstock. But in my opinion from a fitting standpoint is to use a threaded barrel verses a Trubor. The fitting is a tad more difficult due to having to basically fit two surfaces affecting lockup at the same time. With the threaded barrel you can just fit the barrel as you normally would, then thread the comp on to see where you are at as far as how it clocks, is the gap between comp and slide correct? If not I mill the comp to fit, plus you can always change comps later if you see a new design you would like to try.

Edited by MrPostman
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What would cause that type of build up if that's what it is? It's not copper colored.

I'm sure there is some erosion occurring over time, but your comp looks like what I'm used to seeing. I would assume it is somehow mostly powder fouling since I also only shoot jhp's and cmj's and run a lot of HS-6. It's almost like HS-6 embeds itself in the soft titanium at the baffle walls. I get most buildup at the bottom of the first chamber near the barrel. If your comp hasn't come loose or shifted then erosion would create more clearance between bullet and baffle. If it's tight and clearanced then cleaning it and touching it up with a reamer should get it back to where it was before. Otherwise bullets may have always been striking your comp.

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theWacoKid, on 09 May 2016 - 12:13 PM, said:

I get most buildup at the bottom of the first chamber near the barrel.

I get most of my carbon buildup in the first chamber, but zero erosion (or whatever is causing the bumpy appearance). That's all occurring in the 2nd and 3rd chamber.

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I get most of my carbon buildup in the first chamber, but zero erosion (or whatever is causing the bumpy appearance). That's all occurring in the 2nd and 3rd chamber.

Yes, that's exactly what I've experienced. Compensators handle a lot of abuse considering the hot and highly abrasive particles and gases being expelled at major velocities. I just touch it up and keep digging. I don't think what's happening at the baffles is causing your comp strikes unless it has built up a ridge at the edge.

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I have a comp reamer Tyler so if it needs reamed I can do it. Especially since I am local. That also would give me a chance to check the clearances if you like. I am Anthony if you didn't know who i was.

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Thanks Anthony--I appreciate the offer. I'm a bit of a tool junkie, so this will give me an excuse to buy something. It also sounds like an alignment reamer is a good tool to have on-hand.

I did check for clearance and I can get a .015 feeler gauge all the way around between the slide/comp with the gun in lockup. But while I was checking the clearance, I twisted hard on the comp and was able to move it back and forth a degree or two to each side. Looks like the Loctite is failing. Could be I've found my problem. I'm going to go ahead and order the reamer from EGW along with some Loctite 620 (currently using 603) and hopefully get back to shooting. Seems like it's always something with these Open guns. I just got this one last November and I don't think I've gone more than 3 weekends in a row without some issue cropping up.

Guess I'll be shooting Production or Limited this weekend. At least it will be quieter.

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Ok well if you want a good reamer with a live pilot I would get one from pacific tool and gauge. They make some very good tools and they sell directly to the public.

I looked at the pictures of the ones on PTG's website and it looks like the pilot is pretty short. Made me wonder if the pilot would be long enough to go through the comp and enter the barrel before the cutting portion hit the comp. The EGW has a super long pilot. Do you have the PTG version?

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Thanks But while I was checking the clearance, I twisted hard on the comp and was able to move it back and forth a degree or two to each side. Looks like the Loctite is failing. Could be I've found my problem. I'm going to go ahead and order the reamer from EGW along with some Loctite 620 (currently using 603) and hopefully get back to shooting. Seems like it's always something with these Open guns. I just got this one last November and I don't think I've gone more than 3 weekends in a row without some issue cropping up.

I've had better luck with 620, especially with loose threads, so that's a good choice. I finally also tried using 7649 primer as well and it really helps.

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