Shotgun barrel clamp Affect on POI

[Hawk21]

Have heard of folks not using barrel clamps on mag ext. due to negative impact of slug accuracy.... is this a myth or legit concern?

[outerlimits]

legit-BTDT.

[Hawk21]

Is the change static where it can be simply be conpensated for after some range time discovering the new POI........ or will it have a varying impact on every shot?

[outerlimits]

you can try two things.  if using a regular clamp, before you install it, loosen the mag tube from the nut about a 1/4 turn.  conversely, you can go with the taccom version that allows you to float your barrel.

[Dan Sierpina]

1 hour ago, outerlimits said:

you can try two things.  if using a regular clamp, before you install it, loosen the mag tube from the nut about a 1/4 turn.  conversely, you can go with the taccom version that allows you to float your barrel.

I use option 1, never had a problem with slugs if the extension had a slight wobble to it before tightening the clamp.

 

[gose]

Depends on the clamp and gun (most likely how parallel barrel and tube are).

I did some testing without clamp, fairly loose clamp and clamp tightened down hard. At 50y, there was no measurable change in POI.  I might just have been lucky, since others have reported different results. If you want to play it safe, dont use a clamp. If you want to use a clamp, test it first.

[Hawk21]

Thanks what clamp are you using.  My setup is 1301 comp with Nordic 10+1 total

[StealthyBlagga]

On 9/13/2017 at 11:21 AM, gose said:

Depends on the clamp and gun (most likely how parallel barrel and tube are).

I did some testing without clamp, fairly loose clamp and clamp tightened down hard. At 50y, there was no measurable change in POI.  I might just have been lucky, since others have reported different results. If you want to play it safe, dont use a clamp. If you want to use a clamp, test it first.

 

This mirrors my experience. With four (4) different shotguns over more than 20 years of competitive use, I have NEVER had any of my guns change zero due to the clamp. I'm not saying it can't happen, but the zero change has not been a problem for me. The guns I've used were one Remington 11-87 with Choate extension plus clamp (I welded on extra steel to stop the clamp deforming) and three Remington Versa Max with various lengths of Nordic extension plus Nordic clamps. Note that I always add epoxy to the clamp to improve the conformity and grip of the clamp to the barrel/extension tube.

 

 

[tattooo]

I have not see any change in poi in my experience either ...

[James3Gunna]

I just switched to one of these for my A5:

 

http://moaprecision.com/cgi-bin/imcart/display.cgi?item_id=magbrace&cat=7&page=1&search=&since=0&status=&title=

 

So I don't have to worry about it ever again.

 

I had my clamp and tube too tight at the Pro Am and it cost me 20 seconds in penalties .

[FunkyTownAggie]

I definitely had a POA/POI change on my JM 930 to the point that I was racking my brain on how to bring the POI down. After some research, I took off the clamp and the POA matched the POI. I now use a taccom clamp and "free float" the barrel.

[Nathan]

I had the issue, I tried backing the extension out a bit, and tried really hard to have the clamp in the same position but it gave me fits.  Usually not bad enough for penalties, except at a match where we shot paper largely covered by no-shoots at 60 yards...  eliminated clamp and have been good to go.

Note that when using a clamp, even when you know POA=POI, you have to treat the extension as if it was your barrel.  You know how guys shooting off a barricade won’t notice they are resting their barrel on it instead of their handguard and can’t figure out why they’re missing?  Same thing.  If you zero off-hand then shoot off a rest, POI shift, and vice-versa.  I know guys who won’t even use a post/wall as side support b/c they experience a change in windage; everything off-hand all the time.

[xtremekramer]

I just switched to one of these for my A5:
 
http://moaprecision.com/cgi-bin/imcart/display.cgi?item_id=magbrace&cat=7&page=1&search=&since=0&status=&title=
 
So I don't have to worry about it ever again.
 
I had my clamp and tube too tight at the Pro Am and it cost me 20 seconds in penalties .

So what makes your barrel free float inside the clamp?


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[xtremekramer]

Does it make a difference in clamp location? Was looking at some pictures last night of 3 gun shotguns and found one that had the clamp closer to the hand guard then I have mine.

 

 

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[xtremekramer]

I definitely had a POA/POI change on my JM 930 to the point that I was racking my brain on how to bring the POI down. After some research, I took off the clamp and the POA matched the POI. I now use a taccom clamp and "free float" the barrel.

Interesting concept, but it doesn’t give a sling point, which is the only reason I have to need clamp mine.


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[GunCat]

On 10/13/2017 at 9:01 PM, xtremekramer said:

 

 

So what makes your barrel free float inside the clamp?


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The MOA clamp is hinged (like a clam shell). When tightened around the mag tube* the “hole” the barrel goes through is large enough to not touch the barrel. If you are at the Blue Ridge match next week look me up and I'll let you check it out first hand. Another benefit of the MOA clamp is the integral QD socket on its side for those times you want to sling the shotgun.

 

* The clamp is sized to fit around the locating groove in the Nordic MXT or MOA tube. It may not fit on other tubes.

Edited October 15, 2017 by GunCat

[PacMan]

Yes, the barrel clamp can change your slug POI.  My M2 has the Nordic extension (10 total), and I got tired of having to re zero after a full cleaning job so I tossed the clamp in parts bin. I haven't used a barrel clamp in quite a few years.  However if you really want a clamp, use this https://taccom3g.com/product/taccom-extension-stabilizer/  Tim came out with this a few year back.