Posted: 8/20/2018 7:20:02 PM EDT
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Let me preface this by saying I am a fan of Faxon. The stuff I've seen on the internet from FaxonNathan has been really helpful and demonstrates that Faxon is rigorous about bringing creative products to the market that work well and are practical. I have had lots of fun using my 11.5in big gunner 5.56 barrel.
My problem is related to the 20 inch gunner profile 5.56 barrel I purchased recently. I rebarreled an old upper I had from a past project and set out to the range for some initial testing (everything was assembled according to spec and I verified headspace was correct using the new bolt I bought for this setup). While trying to get a rough zero at 100 yards with a 6x scope, I found that many of my rounds were not even hitting the massive piece of cardboard I was using for my targets. When they did hit, it seemed they were poking sporadic holes at random places in the cardboard. That was frustrating. I couldn't get any sort of group, so zeroing the rifle was impossible. I was shooting some federal xm193 from a case that I had used successfully with other guns previously. I figured I should chrono the projectiles and see if maybe the velocity was inconsistent since that could maybe lead to the problem I was observing. However, even that was a stretch because this did not look like vertical stringing. I found that velocity was pretty consistent, in the ballpark of 3400fps, which is hot, but that's what you get with xm193. After going down range to check the target, I found that the holes were not all round. I was getting keyholing and all manners of strange shapes, leading me to think that the bullets were disintegrating after leaving the muzzle. continued in next post... |
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...So next I decided to switch up my ammo. I tried PMC X-TAC m193, which chronoed at about 3200fps and some reloads (55gr hornady sp) at about 3175fps. All of a sudden, the barrel started shooting groups, nothing impressive, but at least it performed like a regular AR15 barrel. I had to use the PMC to get a rough zero. Then I went back to the xm193 and no joke, I don't even think I could hit an IPSC target at 100 yards. The xm193 bullets were flying all over the place.
3400fps is fast, but I don't see any way that a 1:8 twist barrel like the gunner would cause jacket seperation due to an excessively fast spin. The bargain basement 1:7 barrels on my beater guns would never do this. The next test was at an action rifle competition that involved a lot of very close cardboard targets. I shot the xm193 to see if I could learn something from the patterning at close range. What I found was that some bullets were still keyholing or disintegrating, even at 5-20 yards. That tells me the bullets are just falling apart immediately after exiting the barrel. This is not simple tumbling down range due to unstable projectiles. The only model that sort of makes sense to me was proposed by one of the other competitors at the rifle match. Maybe there's a burr from the gas port or some other irregularity in the rifling that is slicing through the copper jacketing on the federal xm193, causing the jacket to rip off after the bullet exits the muzzle. If this is the case, then it implies that the other cartridges that shot more normally (PMC and reloads) must have had thicker jackets that were not totally destroyed by the imperfection in the bore. continued again in the next post... |
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...Any other ideas? I'm really disappointed because I expected this barrel to do well with xm193, which is maybe the most common 5.56 out there. Should I just keep running ammo through this thing hoping that it gets broken in and starts grouping? That might cost me more than just buying a brand new barrel, one that works correctly. And I'd rather not have to rebarrel this upper again. I installed one of those MCMR handguards from BCM, which are nearly impossible to get off once you install them.
I'm stuck. |
| Did you contact Faxon yet other than this post? I read on another forum recently that they had to switch who did their QPQ due to QC issues. You may have gotten a bad barrel from one of those lots. I believe the guy had his replaced as the chamber was in rough shape. I would give them a call and they should get you fixed up |
| I have not contacted Faxon directly yet, but will do so shortly. I believe they'll take care of the situation, but the simplest way for them to do that is probably to send a new barrel. I'm just hoping to avoid replacing the barrel if there is an easier way to make the problem go away. I won't hold my breath, but I figured I'd reach out to others and see if anybody else has dealt with a similar conundrum. |
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Have you checked the chamber or looked for any issues with fired brass? I am guessing the issue is with that. They will probably have to replace the barrel if it is one from before they switched their QPQ company. The other person i was talking about was happy with the replacement he received.
Maybe try another 100 rounds or so to see if it will settle in. check the fired brass for any unusual markings. More rounds may work things out. I would check out the chamber bore with a bore scope if possible as well |
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OK, I shot one or two more matches with the 20 in gunner, using some PMC X-TAC ammo because that load seemed to work well enough for sighting in the gun originally. With this load, I was able to engage targets out to 300 yards with no problems. I haven't had a chance to shoot it much further beyond 300 yet. None of this is a surprise since I never had a real problem with the X-TAC. My beef is with the XM193.
After having run a few hundred more rounds through the barrel, I went back out to a regular range and tried shooting the XM193 again at 100 yards. This time, instead of not being able to hit an IPSC size target, I was able to hit my target. Group size sucked big time, like 4+ inches for 5 shots, but it was a lot better than the last time I tried this ammo. I do acknowledge that some barrels just don't shoot XM193 well, but I had higher hopes for this barrel from Faxon. Given that I saw a great improvement after shooting several hundred rounds, I'm hoping that I just need to break this in further. Maybe I'll see even greater improvement in the future. I'll try to update this thread when I have more data using XM193. I just don't know why the heck the gunner barrel performs so poorly with XM193 while shooting other stuff relatively well. My handloads are nothing special, but I was able to get groups just over an inch at 100 yards. One last thing on the 20 in gunner, I tried shooting a few rounds of the 75 grain gold dot LE ammo at 100 yards. Group size was no good, like probably 3-4 inches. This is a very consistent round, should be able to shoot a lot better than that. I hope it tightens up after further break in. As a side note, I had a great time blasting my 11.5in faxon gunner with an SLR adjustable gas block. That might be the softest shooting gun I own. The brake on it helps, but even for a braked gun, this thing is buttery smooth. The dot doesn't move at all when I pull the trigger. |
| I am one of those who had the "residual salts" scaly crap in the chamber of a new barrel. Didn't impact function or accuracy. I took care of it myself after researching. Contacted the rep here via IM and told him my complete story. He was very accepting and was willing to do whatever necessary to remedy the problem. He also told me that due to that issue they had been forced to use another shop to provide quality barrels. Good guy. I'd contact him. Faxon-Pat. |
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Sorry to be so late to the post, been away from ARFCOM for a bit!
That type of accuracy is definitely not what we would expect out of any of our Gunner barrels. Heck, we expect better accuracy out of our 11.5" Gunner than what you're seeing. It's tough to diagnose without have the barrel back here. XM193 isn't the most accurate round, but you should still be seeing 2-3" groups, not 4-10" groups. Send an email over to [email protected] I'll tell Mark to be on the lookout for it and he'll get everything taken care of for you! |
National Account Manager at Faxon Firearms
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As the OP, I just want to give a quick update.
Faxon customer service was super fast to respond to my emails and they provided a paid shipping label for me to send the barrel back so they could look it over. I am most appreciative of their willingness to help figure out the problem, but as stated earlier, I really don't want to send it anywhere. The stupid BCM MCMR handguard I used for the build is impossible to remove without causing major damage. So after unsuccessfully trying to remove the handguard, I decided to conduct further tests of my own. The gunner barrel still does not shoot XM193 well at all. It pretty much sucks. Cold bore shots group the worst at around 4-6 inches for 5 rounds. I've been able to get several 3 inch groups, but come on, I could probably do that with iron sights on a WASR-10 shooting wolf 7.62x39. I won't give up though. 3 inches is a lot better than the 3 foot groups I was getting originally. When I take the same XM193 and shoot it through a cheapo nitrided barrel from PSA, I can get 2-inch groups with a 1x Aimpoint. HOWEVER, I was super happy to see repeated success shooting IMI 5.56. Holy smokes. I shot several sub-1 MOA groups at 100 yards. The Faxon Gunner 20-inch was shooting the IMI M193 5.56 at 1 MOA or better with a 6x scope. I have a hard enough time doing that with a good bolt gun and a 16x or 25x scope. Why in the heck would performance change so much between xm193 and IMI 5.56? They both run within about 50 fps of one another. I think the bullet profile might be slightly different on the IMI load, but the difference is really small, not what I would think could cause such a difference in group size. continued in next post... |
| ...I hated the IMI 5.56 load previously because the bullets would often get stuck in the chamber of my 223 wylde WOA barrel, causing all sorts of problems. But now, I might actually buy more of that stuff given how well it works in the faxon barrel. None of the other factory loads or hand loads I've tried work as well as the IMI 5.56 in the 20 inch Gunner, but it really is only the xm193 that performs badly. The rest of it is good enough, so I'll quit complaining and maybe do some new load development for this barrel. Apparently it works really well if you figure out the right recipe. |