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FX Impact M3 700mm .30 Heavy Liner Concerns

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S

SEBroz

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Feb 12, 2024
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3 or 4 weeks ago, I bought a 700mm heavy .30 liner and have been working out various slugs (bought and cast) without much luck. I initially had decent grouping with 54gr Zan, but it faded away quickly. Since then, I have tried almost every manufactured variant I can find, ordered casting molds in different weights, tried different alloys, all sorts of tuning adjustments, and epoxied a carbon fiber sleeve on with no luck. I recall seeing some people talking about it taking a few hundred shots to smooth out the barrel and grooves, so figured i just needed to shoot it more.

Well, I've got through a ton of ammo and it seems more like the accuracy is dropping off as the shot count goes up, so I figured I would take a closer look at the liner bore to see if thats where the troubles were coming from. I'm seeing quite a few blemishes along the grooves, spots that look like little divets that go all the way around the ID of the lands, and what looks like a straight seam down the length of the ID. Ive gone through it a few times with JB paste, and even Flitz to see if i can get it to help clean it up with no real change.
Take a look (albeit the pictures I've taken aren't exactly the greatest, and definition of the spots isn't as apparent on them) and tell me what you think. I'm also pushing slugs out of the barrel at .2962-.2964", with slugs pushed halfway and backed out measuring a more standard .2989-2990". Most of the worst pitting is within the last 2" getting closer to the choke. I have been wondering how this liner gets dirty so quickly, but now it seems that these spots are scooping bits of lead from slugs and pellets. Is this just a bad barrel? It's been frustrating me since I can't use this rifle until I know I can make responsible and accurate shots. The original .30 liner that came with appears nearly perfect, so I'm guessing either the choke side of the jig or the liner blank itself had nasty bits stuck to it before it was formed.

PXL_20240506_215624924.PORTRAIT.ORIGINAL.jpg


PXL_20240506_220144066.PORTRAIT.ORIGINAL.jpg
 
The metal used to make the tube may have had a foreign substance in it causing deposits on the finished product. Or it could have been caused by tooling. Either way, use it to stir paint and order another one. If firewalker wants it, don’t sell it, give it to him. You might be able to return it if the place you got it from is cool and trusts that you didn’t screw it up. To lap that out you will wind up with a 31 caliber smooth bore.

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Firewalker said:
Clean and polish your liner. I suggest hand lapping, polishing and waxing the liner.
Click to expand...
I've used JB non-embedding compound on a trimmed cotton bore swab, then moved to Flitz after that. I know I've got a tub of actual Brownells bore lapping compound somewhere around, I could try that, but the pictures don't really show the severity.
There are some old techniques for slugging a bore with pitting like this, but I think I may have just got a Friday Afternoon Barrel.
 
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Vetmx said:
The metal used to make the tube may have had a foreign substance in it causing deposits on the finished product. Or it could have been caused by tooling. Either way, use it to stir paint and order another one. If firewalker wants it, don’t sell it, give it to him. You might be able to return it if the place you got it from is cool and trusts that you didn’t screw it up. To lap that out you will wind up with a 31 caliber smooth bore.

View attachment 462891
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I'll give it a little bit more attention before I turn it into yard art. I was also just curious if receiving them in this condition is standard, or do I stand a chance at getting something better if I order another.
I have a heavy 1:16 .25 barrel that's dead one, but who knows I do the .30 jig/fixture is causing it?
Since most of the really bad spots are closer to the crown and choke, aside from the seam, I could also cut ~1.5-2" and crown to see how that ends up. I've seen mention of these liners prefering to keep their chokes, but now it doesn't look like there is much to lose.
 
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I have a stack of liners and never seen that kind of issue before. I think the odds are in your favor that you’ll get a nice one next time. Firearms with bores like that get a new barrel. If you’re shooting slugs out of a pellet gun, it’s even more important. Reason? You don’t want to be second guessing it. We already second guess enough with slugs.
 
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Vetmx said:
I have a stack of liners and never seen that kind of issue before. I think the odds are in your favor that you’ll get a nice one next time. Firearms with bores like that get a new barrel. If you’re shooting slugs out of a pellet gun, it’s even more important. Reason? You don’t want to be second guessing it. We already second guess enough with slugs.
Click to expand...
Well put. And I'll be ordering another in the morning. Will have to give the new one an examination right out of the tube though.
 
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Yeah, I ordered a replacement from Utah yesterday, which does have the "*not a returnable product in the description".
In the comments I did ask for them to please inspect the liner before shipping, letting the know about the issues from the the current one (also bought from them). Will have to see if they actually do that though. When I ordered the rifle, the test/inspection card did show they used 18.9gr JSB to test and log velocity on a .30cal, although it may have just been an oopsy when filling it out.
 
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Firewalker said:
Clean and polish your liner. I suggest hand lapping, polishing and waxing the liner.
Click to expand...
Came here to say the same. I use JB bore paste. iosso also works great, it’s a bit more gritty than JB. Give it 25 passes with a .30 bore mop, clean with a CLP or similar and I’d even run a patch of alcohol down it at the end to make sure you got everything clean and out. Heck I’ve put over 100 passes of JB bore paste down my superior and superior heavy liners. They 100% both got better as time went on. Had the exact same problem you did when I got my heavy liner.
 
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