Detachable handles and gas blocks

[ZainAnak]

Hey everyone. Two technical questions for you-

1) How far out do detachable A2 carry handles sight for, and why are they different from attached ones? Seems like an identical mechanism to me (?)

2) I'm curious about gas blocks and location on the barrel- if you buy a barrel from one mfr and a free float handguard from another, how can you be sure the gas block and free float tube will match up? Are gas blocks movable (I'd assume they're not, but I've never peeked below the plastic before.) Are there standardized distances for each length barrel (16", 20", 24") for where the block is located?

Thanks!
-ZA

 

[Davidk]

The difference is not so much in their usability but their flexibility. Having a removeable handle allows you have a flat top rail which is a far better choice for mounting optics. If you dont want to do that you, still have the handle.

There certainly is a possiblity that a rail from one company may not fit over the gas block of another. If you buy a low profile design they should fit, but its not a guarantee.

Samson Manufacturing sells quality free float rails and they offer a gas block as well.

 

[ZainAnak]

The difference is not so much in their usability but their flexibility. Having a removeable handle allows you have a flat top rail which is a far better choice for mounting optics. If you dont want to do that you, still have the handle.

But I've heard numerous times that a detachable handle is bad for high power because I'd be in trouble at 600y, due to a narrower sighting range or something to that effect.

 

[M1911]

The main reason it is bad for highpower is because it doesn't qualify for Service Rifle -- local matches won't harass you but it won't fly in important matches.

I used my detachable handle Colt in a few matches and didn't have any problems at the 600 yard range.

But if you are serious about Service Rifle shooting, get a fixed handle.

 

[bpm990d]

The main reason it is bad for highpower is because it doesn't qualify for Service Rifle....

But if you are serious about Service Rifle shooting, get a fixed handle.

The CMP changed the rule and NRA followed suit to allow a detachable carrying handle about two years ago. The reason being is that all of the rifles that recruits used in basic training were M-16A4s with the detachable handle.

You may have a problem getting enough elevation out of the rear sight to go to 600 yds depending on the type of handle you have but many people report no problem. If you want to shoot 1000 yds with it, you are probably stuck as you will need about 23 minutes of elevation beyond your 600 yd zero (in a combination of front and rear sight adjustments) that you probably wont get without a fixed handle.

B

 

[ZainAnak]

The CMP changed the rule and NRA followed suit to allow a detachable carrying handle about two years ago. The reason being is that all of the rifles that recruits used in basic training were M-16A4s with the detachable handle.

You may have a problem getting enough elevation out of the rear sight to go to 600 yds depending on the type of handle you have but many people report no problem. If you want to shoot 1000 yds with it, you are probably stuck as you will need about 23 minutes of elevation beyond your 600 yd zero (in a combination of front and rear sight adjustments) that you probably wont get without a fixed handle.

B

Interesting. Now, to the root of my question- what, mechanically, is the cause for that? How do the two differ such that elevation ranges are less in the detachable?

 

[cdkayak]

You may have a problem getting enough elevation out of the rear sight to go to 600 yds depending on the type of handle you have but many people report no problem. If you want to shoot 1000 yds with it, you are probably stuck as you will need about 23 minutes of elevation beyond your 600 yd zero (in a combination of front and rear sight adjustments) that you probably wont get without a fixed handle.

B

bpm990d beat me to the answer.

The reason you're limited on elevation is the the threaded post that the elevation drum rotates around is shorter on the detached carry handle. The A2 fixed handle allows the post to extend a little lower into the receiver.

CD

 

[ZainAnak]

Makes sense. Thanks!

Speaking of which- any thoughts on this:

http://www.rockriverarms.com/item-d...age=nmcrry.gif&CFID=33809085&CFTOKEN=24319052

which seems to claim "true 0-600 yard" capability?

 

[M1911]

The CMP changed the rule and NRA followed suit to allow a detachable carrying handle about two years ago. The reason being is that all of the rifles that recruits used in basic training were M-16A4s with the detachable handle.

Ah, ok. As you can see, it's been a while since I competed...

ZainAnak: One bit of weirdness that I have with my detachable carry-handle AR is that the front sight post has to be really cranked up in order to get a reasonable zero. Dunno if that's typical of the breed or unique to my example.

 

[bpm990d]

They set them up so that they have a little more adjustment. I have one. It is a nice sight, but have not had it on a dial indicator to test it.

B

 

[LoginName]

Ah, ok. As you can see, it's been a while since I competed...

ZainAnak: One bit of weirdness that I have with my detachable carry-handle AR is that the front sight post has to be really cranked up in order to get a reasonable zero. Dunno if that's typical of the breed or unique to my example.

You might have the wrong front sight post installed. You can buy one that's .040 taller.

As far as different gas blocks...

There's is a difference in location between a 16" barrel and 20" barrel (I'm uncertain if there's a difference between a 20" and 24").

The gas block on an AR is actually the front sight tower. There are aftermarket gas blocks available, but the majority of them are simply front sight towers that have been cut down.

The only gas block that's "under the plastic" that I'm aware of, is on the Bushmaster Dissipator (16" barrel with a 20" sight radius).

Replacing one can be as simple as installing one that uses set screws to clamp it down, or buying one that needs to be drilled by a competent gunsmith so that it's timed correctly in relation to the rear sight/receiver (that's why 99% of the aftermarket barrels out there come with the front sight tower already installed... it's the one part that you can't simply buy
and expect it to correctly fit any AR).

 

[M1911]

You might have the wrong front sight post installed. You can buy one that's .040 taller.

What's most weird is the height of it in relation to the ears -- I have to crank it up so that the front sight post is above the protective ears, IIRC.

 

[cdkayak]

Tall front sight post

I've had to use this on two rifles.

 

[LoginName]

What's most weird is the height of it in relation to the ears -- I have to crank it up so that the front sight post is above the protective ears, IIRC.

I didn't know it could be raised that high.

 

[M1911]

I'll have to take another look at it when I get home...