Gas Block Question

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Posted: 7/27/2009 7:08:40 AM EDT

I bought a micro gas block. It is a super tight fit to get it on my barrel and I am having problems getting it all of the way down to the gas port. Any suggestions on how to handle this? I considered using a dremmel with a sand paper attachment and grinding it down a little. I just don't want to mess up the finish on the barrel if I can help it!

Posted: 7/27/2009 8:04:53 AM EDT

[#1]

I'm assuming you've already tried a plastic mallet of some sort?

Posted: 7/27/2009 8:14:19 AM EDT

[#2]

I am just a noob but on crankshafts i assemble to get gears on we heat the gear up and slide it on with welders gloves. cools and is tight. Can that be done on gas blocks? Set on hot plate few minutes.

Posted: 7/27/2009 9:11:54 AM EDT

[#3]

If you're going to sand anything, sand the gas block, not the barrel. Always modify the cheapest part. Get a set of calipers and check the OD of the barrel and ID of the gas block. If they don't match up then whichever is defective, return it to get it fixed. If they do match up then try one of the above suggestions.

Posted: 7/27/2009 9:20:58 AM EDT

[#4]

Quoted:
I'm assuming you've already tried a plastic mallet of some sort?

You know what Assume means now don't you?!? I have not tried the mallet simply because of how tiny the gas block is (cmmg micro) and if there was a better way (one that would screw up the finish of the barrel) I would rather try that first. Keep the ideas coming so that I have some options tonight!!

Posted: 7/27/2009 11:44:57 AM EDT

[#5]

Quoted:

Quoted:
I'm assuming you've already tried a plastic mallet of some sort?

You know what Assume means now don't you?!? I have not tried the mallet simply because of how tiny the gas block is (cmmg micro) and if there was a better way (one that would screw up the finish of the barrel) I would rather try that first. Keep the ideas coming so that I have some options tonight!!

It is probably just the finish on the inside of the gas block that is causing the problem. I would take some fine sandpaper and rap a small piece around your pinky finger and insert it inside the gas block and twist. The dremmel may take to much off of one side or the other and then the gas block is not going to fit right. And as posted above I would not sand or grind on the barrel.

Posted: 7/27/2009 1:15:13 PM EDT

[#6]

The absolute last thing I would do is grind/sand it.

Along with what Texjames said:
I'd freeze the barrel and heat up the gas block. Many manual transmissions have extremely tight clearances that require this method for installing gears on the mainshafts

Posted: 7/27/2009 1:51:02 PM EDT

[#7]

I've only had one gb that had an interference fit. I just used a hair dryer to apply heat. Just make sure the placement is correct.

Posted: 7/27/2009 2:27:13 PM EDT

[#8]

Quoted:
The absolute last thing I would do is grind/sand it.

Along with what Texjames said:
I'd freeze the barrel and heat up the gas block. Many manual transmissions have extremely tight clearances that require this method for installing gears on the mainshafts

Yeah its amazing how tight they can get when cool and have to be pulled off with a puller but slip right on hot.

Posted: 7/29/2009 6:33:56 PM EDT

[#9]

Quoted:
If you're going to sand anything, sand the gas block, not the barrel. Always modify the cheapest part. Get a set of calipers and check the OD of the barrel and ID of the gas block. If they don't match up then whichever is defective, return it to get it fixed. If they do match up then try one of the above suggestions.

I am having this same issue on my first build. I am not a machinist by any means and might be slightly off with my measurements but when I checked the gb, one side of the block was .750 and the other .745. The gb would only slide about 1/4" down the barrel. I sent it back to the manufacturer yesterday. Since I am a noob and don't know any better that was my solution. Hopefully it will come back with the correct diameter.

260

Posted: 7/30/2009 7:57:02 PM EDT

[#10]

Victory!. I tried cooling the barrel and heating the block but it didn't help. I think that choosing one or the other might be better but I don't have that kind of patience. So, I wrapped a towel around the block and used my channel lockers to grip the block and then spun the block around the barrel like I was threading it on. It took a little work but it eventually made it there. It will officially go bang (repeatedly).

Posted: 7/31/2009 2:28:31 AM EDT

[#11]

Quoted:
Victory!. I tried cooling the barrel and heating the block but it didn't help. I think that choosing one or the other might be better but I don't have that kind of patience. So, I wrapped a towel around the block and used my channel lockers to grip the block and then spun the block around the barrel like I was threading it on. It took a little work but it eventually made it there. It will officially go bang (repeatedly).

Glad you finally got it on there.
Range report needed

Posted: 7/31/2009 4:25:52 AM EDT

[#12]

Quoted:

Quoted:
Victory!. I tried cooling the barrel and heating the block but it didn't help. I think that choosing one or the other might be better but I don't have that kind of patience. So, I wrapped a towel around the block and used my channel lockers to grip the block and then spun the block around the barrel like I was threading it on. It took a little work but it eventually made it there. It will officially go bang (repeatedly).

Glad you finally got it on there.
Range report needed

Hoping to sight it in this weekend. I will give you an update.

Posted: 7/31/2009 7:10:50 AM EDT

[#13]

I use a 100 watt light bulb in a trouble light to heat up bearings and gas blocks if needed.

Posted: 8/3/2009 10:42:32 AM EDT

[#14]

Quoted:
I use a 100 watt light bulb in a trouble light to heat up bearings and gas blocks if needed.

I used my wife's hair dryer. That didn't go over well. Apparently it is really expensive and it had be on for 15 minutes or so when she heard it

.

Didn't do much but sight it in but it ran B E A utifuly (not breaking out the rulers for group sizes because any poor performance would be me and not the gun but I was happy with how it went). Mission Frankenkiller complete. Now to actually do some real practice at the farm!!

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