Surefire 300 SPS First Round Velocity

staticTango

Private
Minuteman
Apr 9, 2010
40
2
43
Blacksburg, VA
I have a new surefire socom 300 sps and did a load development ladder with my 26” 6GT.

I was shooting 5 round groups, then letting the barrel cool for 5-10 min before repeating with the next load. I consistently noticed the first round fired in each series was about 80 fps slower than subsequent shots. Is this a bi-product of using this suppressor vs a different design?

Also, I noticed most of the first rounds were being drastically thrown versus the following 4 shots. I tried removing / re-mounting the suppressor and it seemed to fix the shift issue for a couple groups, but then it returned. Meaning the first shot would land 1.5-2” away from the following shots, which would be within a .6” group.

I noticed this same first shot thrown behavior with 6.5 creedmoor rifle I have as well.

I’m kind of disappointed for a $1k suppressor. Kind of wish I had purchased a Thunder beast.

Any thoughts, advice, prior experience?

Thanks!
 

Mrindecisive

Private
Full Member
Minuteman
Supporter+
Apr 8, 2017
164
77
30
Ohio
I had a similar issue with first round impact with my sps. The first round would be up to 5in away, the rest would be within .5in. I did not note velocity. I wish I would have. I checked that I installed the muzzle device correctly and the suppressor to the muzzle device. After it constantly did this I sent it back to SF, where it has been for 8 weeks. I should get my TBAC dominus out of jail soon.
 

Terry Cross

Dingleberry
Supporter
Commercial Supporter
Full Member
Minuteman
Supporter+
Mar 15, 2003
1,952
4,994
Alexandria, LA 71303
www.kmwlrs.com
I have a new surefire socom 300 sps and did a load development ladder with my 26” 6GT.

I was shooting 5 round groups, then letting the barrel cool for 5-10 min before repeating with the next load. I consistently noticed the first round fired in each series was about 80 fps slower than subsequent shots. Is this a bi-product of using this suppressor vs a different design?

Also, I noticed most of the first rounds were being drastically thrown versus the following 4 shots. I tried removing / re-mounting the suppressor and it seemed to fix the shift issue for a couple groups, but then it returned. Meaning the first shot would land 1.5-2” away from the following shots, which would be within a .6” group.

I noticed this same first shot thrown behavior with 6.5 creedmoor rifle I have as well.

I’m kind of disappointed for a $1k suppressor. Kind of wish I had purchased a Thunder beast.

Any thoughts, advice, prior experience?

Thanks!
Are you cleaning the bore prior to the velocity drop?

.
 
  • Like
Reactions: HenryTheAce

staticTango

Private
Minuteman
Apr 9, 2010
40
2
43
Blacksburg, VA
Not cleaning the barrel. I shot 50 rounds in 5 shot strings…waiting 5-10 minutes between strings. Wasn’t even moving the rifle off the rest between strings. Has anyone had better luck with the muzzle brake vs flash hider? I was using flash hider.
 
  • Like
Reactions: Terry Cross

Terry Cross

Dingleberry
Supporter
Commercial Supporter
Full Member
Minuteman
Supporter+
Mar 15, 2003
1,952
4,994
Alexandria, LA 71303
www.kmwlrs.com
Not cleaning the barrel. I shot 50 rounds in 5 shot strings…waiting 5-10 minutes between strings. Wasn’t even moving the rifle off the rest between strings. Has anyone had better luck with the muzzle brake vs flash hider? I was using flash hider.
No clue what is going on with yours.

I have seen a lot of the SF suppressors act like squirrels for no reason. The legacy models were terrible but some think it traced back to bad lots of adapter mounts that weren't concentric ID/OD.

In spite of a lot of pissed off experiences with SF, I have never seen a velocity drop like that.

.