bjcollado Posted August 2, 2014 Share Posted August 2, 2014 hi, guys. i was wondering if any of you have experience or have you heard of a certain type of barrel being incompatible with a particular kind of comp. i recently had a used barrel be refitted with a new comp. my problem is, whenever we try to zero it, we notice that the bullet hits a comp port and the bullet tumbles/keyholes. so when we ream that particular part of the comp and go back to the range to zero, the bullet hits another part of the comp again! so this morning, after reaming the part where the bullet hits the comp port for the third time, we tried to zero it and lo and behold, it now hits another port of the comp! the gunsmith says that the problem must be with barrel. but we can't find anything wrong with the barrel. i had it re-crowned also just to be sure but still same problem. so now i just had a conversation with a buddy of mine who also had his old barrel be re-fitted with this particular kind of comp and he has the same problems as I. his gun shot straight and grouped well before but since he put in this new comp, he also was not able to zero and group his shots (lots of flyers). he and i have the same kind of barrel (schue rib type hybrid). we are baffled because other shooters who have the same kind of comp as us but have another kind of barrel do not have the problems that we have! is it safe to say that the comp is the problem with our guns or is it our barrel? btw, my friend says that when he took out the comp and shot groups with his gun without any comp, the shots grouped tight. Link to comment Share on other sites More sharing options...
Toolguy Posted August 2, 2014 Share Posted August 2, 2014 (edited) It sounds like the comp is moving around on the barrel. Maybe the threads are too loosely fitted. If the comp is fitted right and tight on the barrel the bullet won't be hitting the comp. A reamer is not the way to align the hole in the comp with the bore of the barrel. Even though the reamer has a pilot that goes in the bore, the reamer will still follow the original comp hole to some extent. The right way is to put the barrel in the lathe chuck and use a boring bar to do the hole in the comp. The boring bar will make the hole straight and true to the bore and not follow the original hole. The comp has to be very solid on the barrel first though. If the barrel shoots good without the comp then there is something wrong with the installation. If the bullets are hitting the comp, there is something wrong with the installation. Edited August 2, 2014 by Toolguy Link to comment Share on other sites More sharing options...
LoganbillJ Posted August 2, 2014 Share Posted August 2, 2014 The comp design may be the reason for your fliers. I recently designed a few comps for my glock. Some would hold a great pattern, others looked like a shotgun pattern. No baffle strikes on any of them. The baffle design can have a huge effect on your accuracy. Be sure your barrel shoots great without the comp. Then work from there. Follow toolguy's advice for the comp. He nailed it. Btw what is is your comp reamed to and what are you shooting? Link to comment Share on other sites More sharing options...
goldfieldshooter Posted August 3, 2014 Share Posted August 3, 2014 Have a stepped guide made up. Approx 4" long. 1.5" turned to bore dia the rest turned to comp bore dia. Use it to install and align the comp everytime you take it off and put it back on. You can also use it as a check tool to make sure things haven't moved. BTW comps should not move if made and fitted right. Mine now go against a shoulder with a crush fit. Been bitten once too many times. Link to comment Share on other sites More sharing options...
Iceman2733 Posted August 3, 2014 Share Posted August 3, 2014 (edited) This sounds like a very odd problem like others have stated make sure threads are correct and no play. Also was your friend comp fit by the same gunsmith? Just asking for info might help Just for more info what comp is that? It looks killer Edited August 3, 2014 by Iceman2733 Link to comment Share on other sites More sharing options...
gng4life Posted August 3, 2014 Share Posted August 3, 2014 I'm with toolguy also. I had similar issues with very popular comp and barrel combination that should work together. I ended up going with a different comp (not due to this) and this other gunsmith (Ortiz Custom) fit it right and no problems since then. It's important to run the bar through it versus just reaming the hole. One other thing to add...there is a certain correlation between barrel, comp, and slide weight. Mr. Gans told me about it once so you should try to match these up correctly. Link to comment Share on other sites More sharing options...
bjcollado Posted August 3, 2014 Author Share Posted August 3, 2014 (edited) thanks for the input, guys! toolguy, yup, i think the comp is fitted tightly with the barrel with no movement at all. i'm not familiar with the process of making a comp, but from what i saw, when they made it, there was just a rectangular piece of metal attached to the end of my barrel. then the gunsmith said that they were going to bore a hole through there to make sure that there will be no alignment issues. logan, i was also pondering on that possibility. can it really be a design issue? btw, if you guys notice the two small ports at the end of the barrel, just before the big ports of the comp? that is what the gunsmith is blaming the problem for. he says that the bullet cannot make a full turn before exiting the barrel that why it already starts to tumble as soon as it leaves the barrel and that's why the bullet is hitting the bafles. is that also a possibility? i also checked the diameter of the port by putting a bullet head through it. the bullet has a lot of wiggle space just like what the GS says. however, i already did my research and i gathered that the porting of the barrel should not cause the tumbling as long as the crown is intact. yes, my friend and i have the same gunsmith and they don't mass produce their comps. they get the customer's barrel first and they they start from there. i'm not panicking right now but i will be soon because that's the gun that i'm gonna use for the World Shoot this October! my practice gun also gave up on me last week due to slide cracking also. sigh. Edited August 3, 2014 by bjcollado Link to comment Share on other sites More sharing options...
jid2 Posted August 3, 2014 Share Posted August 3, 2014 No offense but whoever designed that comp and porting layout is simply throwing random features into the system without understanding how they work together. That comp is heavy and wasting most of its potential based on its size. As others said, what size is it currently reamed? Do you have access to a lathe? Link to comment Share on other sites More sharing options...
Aircooled6racer Posted August 3, 2014 Share Posted August 3, 2014 Hello: What barrel is it? I would remove the comp and shoot it to see if it still tumbles the bullets. If so then it is the barrel setup. If not then it is hitting the comp. Thanks, Eric Link to comment Share on other sites More sharing options...
bjcollado Posted August 4, 2014 Author Share Posted August 4, 2014 None taken, jid2. Ac6r, it's a schuemann hybrid .38super. I think the comp ream diameter is already at .385 guys. Is there still room to make it bigger? Link to comment Share on other sites More sharing options...
LoganbillJ Posted August 4, 2014 Share Posted August 4, 2014 You can make it as large as you want. The problem is the larger you go, the less efficient your comp is. Link to comment Share on other sites More sharing options...
BeerBaron Posted August 4, 2014 Share Posted August 4, 2014 I'm a long way from being an expert, but have some annecdotal experience with open guns. the 3 main ports in that comp are HUUUGE. I'm not 100% convinced on the first 2 v ports in the barrel. given it has 4 large barrel ports along with a big multi chamber comp it must be so load. are you able to observe how/where the gas exits the comp? it seems like a massive and heavy comp and with the massive main chambers I can't see much gas reaching the end V chambers. ports drilled into the chamber are generally put in a place where they won't disturb the rifling if possible. but then guns like the tanfoglios have 8 ports in the barrel (they are much smaller though and much wider spaced in a V, with 4 down each side) and they don't cause tumbling. perhaps jid2 or aircolled racer can give some more advice, but they've suggested some tests. I'd go and do those tests and report back. it may help narrown down the culprit. apart from the tumbling how does the gun behave? I'm guessing it's damn noisy!!! Link to comment Share on other sites More sharing options...
bjcollado Posted August 12, 2014 Author Share Posted August 12, 2014 so i finally shot it without a comp and guess what, guys, no fliers! explained this to the GS and he generously offered to refund me in full for the comp. so now i am going to have one built and now i am confused on what to have built, the one where the ports go from big to small or the ones where it starts from small to big like the Akai types. Link to comment Share on other sites More sharing options...
limited shtr Posted August 12, 2014 Share Posted August 12, 2014 Buy a cheely ti comp it works the the best for me I have every comp from every top gun smith and the cheely is better than the rest Link to comment Share on other sites More sharing options...
bjcollado Posted August 12, 2014 Author Share Posted August 12, 2014 Jid2, saw your post on comp design. you think your design can work on my barrel? Link to comment Share on other sites More sharing options...
bjcollado Posted August 12, 2014 Author Share Posted August 12, 2014 limtd shtr, i'm not from the US so i don't have access to cheely and other gunsmiths there. so best i can do is have one made. Link to comment Share on other sites More sharing options...
BeerBaron Posted August 13, 2014 Share Posted August 13, 2014 can you order something like a brazos thundercomp? Link to comment Share on other sites More sharing options...
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