This is a repost of a test a good buddy of mine did that I thought I would share with you all. This test shows why I use the BCG's I use in my Marksman line of rifles where getting every bit of accuracy out of a rifle is critical.
An effort to strive for consistency from shot to shot has brought me to this..........Trying to see if anyone else has had the same thoughts or tried to validate which carrier to use. I ordered some stuff from JP Friday and while I waited I was talking to a fella named Ben. I asked a question about using an ultra light carrier on my Grendel. He said I may not want to because the Grendel is on the higher end of an AR15 and bolt lockup may be in question. He wasn't sure if the LowMass would have any issues or not. I said I'd try it this weekend and see. So here it goes. I almost refuse to use a full mass carrier, non silent capture buffer or a non adjustable gas block anymore on a personal AR. So it made me think to check this for this build. (I'm still shooting Mike's Grendel waiting on all my pieces) I grabbed my Rubber City Armory low mass carrier, Mike's Colt Full mass carrier and Chase's JP LowMass for the weekend. (all are 5-10k round carriers already from 5.56 guns). I've tried this test twice with nearly identical results. I fully understand that loading the bipod, pressure from my shoulder and placement of my shooting bags can effect this. I tried to mitigate this by putting it on a 6x6 post that supported one of the bay's overhangs and my pump pillow. Then I tuned each carrier only to lock back plus a quarter turn more and waited an hour by goofing off in the pistol bays. These are the results. All used the same JP Bolt as that's the only 6.5 Grendel bolt I have.
1 min between rounds and 1 hour between runs(had fun in the pistol bays while I waited, lol)
Colt Bolt Full Mass Carrier Friday afternoon's 5shot string: 2517, 2519, 2524, 2528, 2532fps Saturday's: 2514, 2518, 2524, 2529, 2536
Rubber City Armory LowMass Carrier: Friday's 2478, 2493, 2486, 2508, 2503fps Saturday's: 2469, 2478, 2486, 2499, 2487
JP LowMass Carrier: 2523, 2521, 2527, 2529, 2526fps Saturday's 2519, 2521, 2524, 2527, 2529
These differences in fps will not matter in a 100 yard zero. They will however matter over distance and winds. As a side note this was all done using factory AMAXs from the same two boxes. Has anyone tried anything like this if so what where your results? I blindly answered a best carrier question the other day on here and didn't know how else to even check my statement.....Also I am not affiliated with anyone on this but if Hornady reads this I would love for them to send me some more ammo..... Lol. It did ridiculously well for this test.
Rubber City Armory LowMass BC: 13AUG: 2481, 2488, 2513, 2496, 2508 25AUG: 2491, 2485, 2508, 2479, 2496
JP LowMass BC: 13AUG: 2520, 2529, 2527, 2531, 2534 25AUG: 2526, 2533, 2536, 2529, 2538
JP UltraLowMass BC: 13AUG: 2524, 2529, 2531, 2523, 2535 25AUG: 2525, 2526, 2531, 2533, 2536
NightOps BC: 13AUG: 2527, 2532, 2536, 2528, 2524 25AUG: 2526, 2531, 2528, 2536, 2539
5 shot group with the JP Low Mass Carrier
5 shot group with the JP Ultra Low Mass Carrier
5 shots with the Night Ops Carrier (don't worry about that flyer I pulled that and shot an extra round for my screw up
Top Left Rubber City BCG, Top Right JP Low Mass, Bottom Left JP Ultra Low Mass, Bottom Right Night Ops BCG