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OldState
03-09-11, 11:38
I have searched and have not found this so I thought I would ask.

Does anyone make a low profile gas block designed like a "shaved" FSB?
Or in other words, is there a "drop in" pinned option available that doesn't need modification to the block or the barrel?
ASH556
03-09-11, 11:48
I don't think it would be possible. The location of the pins on a FSB is different on every rifle. (i.e. you cannot take the FSB off of one rifle and put it on another) Now I'm sure someone somewhere found two that were close enough, and got it to work, but as a general rule, they are not interchangeable.
OldState
03-09-11, 12:02
OK. I didn't realize that but I had considered it in the realm of possibilities.
I could not otherwise understand why no one would make something like this.
Now I'm wondering how different the specs are between manufactures.
Anchor Zero Six
03-09-11, 12:30
Would this work for you?

http://www.rainierarms.com/?page=shop/detail&product_id=1398

http://www.rainierarms.com/?page=shop/detail&product_id=588

pins available here

http://www.dpmsinc.com/store/products/?prod=772&cat=1798
OldState
03-09-11, 16:25
Thanks for the links. Can you not use the taper pins from the FSB?

I'm assuming the next more secure method would be set screws and dimple the barrel(?).
Anchor Zero Six
03-09-11, 16:27
Yeah you can reuse pins just in case one runs away from ya its good to know where to get spares.
RichDC2
03-09-11, 16:29
taper pins are drilled into the barrel with the fsb in place. they are unique to each barrel, your best bet would be a clamp on gas block if you dont want to modify your barrel
Anchor Zero Six
03-09-11, 16:35
How are taper pins drilled in? I have only seen fixtures used to drill or milling machines. In either case the fsb/gb is not in place.

Sure there are many ways to do this so dont take it as a pissing contest just wondering how else it can be done.
OldState
03-09-11, 16:35
taper pins are drilled into the barrel with the fsb in place. they are unique to each barrel, your best bet would be a clamp on gas block if you dont want to modify your barrel

I can't believe they have not standardized this in a platform that's know for its interchangeability.:(

From what I've read there are some concerns about clamping the block but I have not found any posts claiming actual failures.
kartoffel
03-09-11, 18:51
By the time you've re-drilled and re-reamed for a new gas block, you've got as much time and labor invested as simply shaving your existing front sight.

But I agree that pinned gas blocks are the correct way to go. Clamps and set screws are strictly bush league.
another-bill
03-13-11, 21:21
I have moved a Bushmaster shaved FSB/Gas Block from one Bushy barrel to another with no ill effects.

I realize that it doesn't work with a sight as it will be off, but for a gas block, it worked for me that time.





Bill
RAM Engineer
03-13-11, 21:49
I can't believe they have not standardized this in a platform that's know for its interchangeability.:(

From what I've read there are some concerns about clamping the block but I have not found any posts claiming actual failures.

It's all about getting the tightest fit between the FSB and the barrel, to prevent gas leaks and misalignment. THAT is why each one is done individually.

The FSB has tolerances, the barrel has tolerances, but by being drilled/reamed together, those tolerances don't matter (as much) and the FSB is held PRECISELY over the gas hole.
wetidlerjr
03-14-11, 06:01
...From what I've read there are some concerns about clamping the block but I have not found any posts claiming actual failures.

I would like to know about failures as well.
OldState
03-14-11, 08:31
I would like to know about failures as well.

I did find this is an old post here:

http://www.militarymorons.com/weapon...s2.html#torque

Being that I intend this to go UNDER a free float hand guard I'm thinking a clamp on will do the trick. Also, I would prefer to not cut/drill the barrel of my new Colt.
wetidlerjr
03-14-11, 10:08
I did find this is an old post here:
http://www.militarymorons.com/weapon...s2.html#torque...

Thanks ! :D
Anchor Zero Six
03-14-11, 10:23
If you intend to have the GB under a handguard I would not hesitate to use a set screw type GB.
OldState
03-14-11, 14:39
If you intend to have the GB under a handguard I would not hesitate to use a set screw type GB.

Unless I dimple the barrel I would think the clamp would be more secure (see link above).

Also if I want to put the rifle back together stock, I can with no barrel modification.
Anchor Zero Six
03-15-11, 09:59
Link not working for me.

By dimpling do you mean dimple for the set screw or dimpling the barrel to cut weight?
opmike
03-15-11, 11:21
Link not working for me.

By dimpling do you mean dimple for the set screw or dimpling the barrel to cut weight?

Dimple for the set screws.
Anchor Zero Six
03-15-11, 11:39
Gotcha, just checking. Sort of sounded like he was thinking of dimpling the barrel to include the gas block area.
OldState
03-17-11, 17:58
Link not working for me.

By dimpling do you mean dimple for the set screw or dimpling the barrel to cut weight?
Try this
http://militarymorons.com/weapons/ar.optics2.html

and here

https://www.m4carbine.net/showthread.php?t=6633