Proper installation of SureFire MB338SS03

[mtang45]

I just had a SureFire MB338SS03 install by my local gunsmith. The barrel was too large in diameter and needed to be turned down to install the muzzle brake. I have another rifle with the same brake in it, and the brake screws right up to the shoulder with no gap between the brake and the barrel shoulder. The new install has about .25" gap between the base of the muzzle brake and the barrel shoulder (see picture). When I asked about the gap they told me it was installed correctly and that SureFire instructions indicate that a gap is required. I'm having doubts about that statement and think this is the ugliest install that I have ever seen. What do you think?

 

[nn8734]

I just had a SureFire MB338SS03 install by my local gunsmith. The barrel was too large in diameter and needed to be turned down to install the muzzle brake. I have another rifle with the same brake in it, and the brake screws right up to the shoulder with no gap between the brake and the barrel shoulder. The new install has about .25" gap between the base of the muzzle brake and the barrel shoulder (see picture). When I asked about the gap they told me it was installed correctly and that SureFire instructions indicate that a gap is required. I'm having doubts about that statement and think this is the ugliest install that I have ever seen. What do you think?

View attachment 8473714

Lol, if you installed that brake with no gap, you'd have no room for the locking collar on the suppressor. The above pic appears correct for those otb legacy SF cans.

Have you been around or seen any M40A5's, A6s or XM3s? They all use the same family of SF cans and every one of those bbls have that gap

 

[mtang45]

My other rifle for reference, which is the only visual I have ever gone by. I'm guessing its the original barrel diameter of the older install that is correct for the brake. Also wondering about the orientation, the new install is 180 degrees out from the original. Like its upside down and needs to rotated another half turn. Orientation in the below pic is you are looking at the top of the barrel on both rifles.

 

[nn8734]

My other rifle for reference, which is the only visual I have ever gone by. I'm guessing its the original barrel diameter of the older install that is correct for the brake. Also wondering about the orientation, the new install is 180 degrees out from the original. Like its upside down and needs to rotated another half turn. Orientation in the below pic is you are looking at the top of the barrel on both rifles.

Here's my A5's brake and can, for reference. The notch on the brake for the suppressor's engagement dowel is at the six oclock position.

 

[mtang45]

Lol, if you installed that brake with no gap, you'd have no room for the locking collar on the suppressor. The above pic appears correct for those otb legacy SF cans.

Have you been around or seen any M40A5's, A6s or XM3s? They all use the same family of SF cans and every one of those bbls have that gap

Thanks for the info. Good to have a confirmation as to a correct install.

 

[mtang45]

Here's my A5's brake and can, for reference. The notch on the brake for the suppressor's engagement dowel is at the six oclock position.

So my brake is a half rotation out.

 

[nn8734]

So my brake is a half rotation out.

Are you referring to the 338 brake? If so, check the engagement dowel on your SF can to see where it's located relative to the alignment dot on the 12 o'clock position on the suppressor. Its just forward of the locking collar.

 

[Rob01]

So my brake is a half rotation out.

Looks that way as the two holes should be on the top of the barrel as they allow blast to go through them and keep muzzle rise down when not using the can. Also the slot is on the bottom. That little cut behind the brake is supposed to be there if the barrel is a heavy enough contour to need it. Looks like your other might not be.

Top

Bottom with alignment slot.

 

[mtang45]

Looks that way as the two holes should be on the top of the barrel as they allow blast to go through them and keep muzzle rise down when not using the can. Also the slot is on the bottom. That little cut behind the brake is supposed to be there if the barrel is a heavy enough contour to need it. Looks like your other might not be.

Top
View attachment 8474149

Bottom with alignment slot.

View attachment 8474150

Thanks for the pics and clarification on top vs bottom.