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badness
10-05-13, 04:21
Is there any known process to fit a .750 gas block to a thinner barrel? I have a KAC fsb that i want to mount to a barrel that has a thinner diameter than .750.

Thanks.
MarkG
10-05-13, 08:03
This ins't a worthwhile project. You'd be better off using a gas block manufactured to fit your barrel.
MistWolf
10-05-13, 08:29
You would have to have a sleeve made to make up the difference, a simple thing for a knowledgeable machinist. Probably best if it were made to be a press fit to the inside of the FSB
badness
10-05-13, 23:39
You would have to have a sleeve made to make up the difference, a simple thing for a knowledgeable machinist. Probably best if it were made to be a press fit to the inside of the FSB

That's what i was afraid of. Thanks Mist.
AlphaKoncepts
10-07-13, 08:56
Plenty of comanies make a .625 FSB. I am assuming that is the barrel size at the gas block? Probably pay the machinist more than it is worth to retrofity your .750 FSB, vs just buying a FSB properly manufactured for your project.
patrick sweeney
10-07-13, 11:25
The consensus is correct; as a "learning how to run a lathe" project, it would be fun. As a "how many ways can you screw up the gas port alignment and gas path size" it would be instructive.

As a cost-effective approach, not so much.
kantstudien
10-07-13, 13:05
Save yourself some pain:

http://www.bravocompanyusa.com/BCM-Low-Profile-Gas-Block-p/bcm-lgb-.625.htm
Ryno12
10-07-13, 13:30
Save yourself some pain:

http://www.bravocompanyusa.com/BCM-Low-Profile-Gas-Block-p/bcm-lgb-.625.htm

I'm guessing the OP wants to use a fsb. This might be more appropriate:
http://www.bravocompanyusa.com/AR15-Front-Sight-F-Marked-625-p/front%20sight%20base%20-%20f%20625.htm

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GH41
10-07-13, 14:08
OP says he has a KAC fsb. If one of these http://www.operationparts.com/KAC_Knights_Armament_Front_Folding_Sight_Gas_Block_p/21342.htm that he bought cheap I can see why he would go through the trouble!! GH
Ryno12
10-07-13, 14:13
OP says he has a KAC fsb. If one of these http://www.operationparts.com/KAC_Knights_Armament_Front_Folding_Sight_Gas_Block_p/21342.htm that he bought cheap I can see why he would go through the trouble!! GH

Yeah, for that price I'd go with pretty much anything else. :eek:

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jmnielsen
10-07-13, 14:37
I think if that is what OP is talking about he should just buy a different barrel.
badness
10-07-13, 14:42
I think if that is what OP is talking about he should just buy a different barrel.

ding ding ding! That's actually what i plan on doing.
Ryno12
10-07-13, 17:31
ding ding ding! That's actually what i plan on doing.

You didn't actually pay that much, did you? I'm pretty sure that even if I won every Powerball jackpot, I'd still never pay that much for a FSB... but that's just me.

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Tzook
10-07-13, 17:48
You didn't actually pay that much, did you? I'm pretty sure that even if I won every Powerball jackpot, I'd still never pay that much for a FSB... but that's just me.

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KAC is legit, but I see some of the prices for parts and I'm like uhhh..... What?
GH41
10-07-13, 19:34
Do I get a prize for solving the riddle?? GH
GH41
10-07-13, 20:02
Jokes aside.. I would turn a 1.125 x .6245+/- bushing and sweat it onto the barrel, chuck the barrel up and turn the bushing to .750 if I had to save a $450 fsb!! GH
Ryno12
10-07-13, 20:31
Jokes aside.. I would turn a 1.125 x .6245+/- bushing and sweat it onto the barrel, chuck the barrel up and turn the bushing to .750 if I had to save a $450 fsb!! GH

Honestly, I'd sell it. The cash invested in that FSB & now a new barrel isn't worth it IMO. Really, what is gained in the end that couldn't be had for less? Believe me, I'm all about quality but there comes a time where it becomes unjustifiable to me.
I'm not biking on the OP, that's his business what he does with his cash.

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badness
10-07-13, 21:22
I got it in a local trade during the "panic" earlier this year. The guy bought it with the intention of building himself an AR. But then couldn't find any parts, so he bought a complete rifle and had no use for it anymore. :haha:
AlphaKoncepts
10-07-13, 23:14
OP says he has a KAC fsb. If one of these http://www.operationparts.com/KAC_Knights_Armament_Front_Folding_Sight_Gas_Block_p/21342.htm that he bought cheap I can see why he would go through the trouble!! GH Yeah if I paid $500 for a FSB I would want to use it. Actually I would not pay $500 for a FSB, and I would sell it to help offset the cost of buying the BCM discussed previously or a DD if they make a .625. I don't know about the BCM, but I like the DD anti glare cuts.
Mall_Ninja
10-11-13, 14:03
I got it in a local trade during the "panic" earlier this year. The guy bought it with the intention of building himself an AR. But then couldn't find any parts, so he bought a complete rifle and had no use for it anymore. :haha:

Dude must have been REAL motivated to build a rifle if the only FSB he could find available was $500!!

You could build over half of a nice rifle for that...

Put a regular gas block on that .625 pencil barrel you got. Then build an upper on a .750 barrel using that Unobtanium KAC you got (you will surely still be ahead or break even) and just walk around showing it off at the range...HAHAHAHA
Packing a 45
11-04-13, 21:34
Fit iy the same way you would fit a 17" truck tire onto a 14" rim.