.22-250, Surefire 762RC2, and its impact on trajectory

[FieldGaugeFailure]

Good morning Gents.

While waiting on a couple cans to get out of jail, I went about testing some of my other cans on one of my 22-250 rifles. While testing my 762RC2, I found some interesting results.

First off, lets talk gear.

• Rifle - Bergara Stoke, 20" barrel, 1:9, 5/8x24 thread
• Ammo - .22-250 Hornady Varmint Express, 55gr
• Muzzle Device - Surfire 7.62 3 prong
• Can - Surefire 762RC2
• BC - .255 (G1)
• MV unsuppressed - 3415 avg, 22.3 STD, 75 ES [75 shots]
  • MV suppressed is ~10-15 FPS faster
• 100 YD zero

Kestrel Predictions 100-400 [mrad]

• 100 - 0
• 200 - .16
• 300 - .64
• 400 - 1.27

While shooting with the 762RC2 can, I deviated from the Kestrel estimations a ton. Field results are as follows:

• 100 - 0
• 200 - .5
• 300 - 1.2
• 400 - 2

Normally, a small deviation will just require a bit of playing with BC or velocity (depending on distance of data), but to try to get the Kestrel to match up with my field results, you would have to drop the numbers a significant amount, to the point where it is no longer a realistic representation of what is going on. Puzzled by the results, I took the can off, re-zeroed and tested with just the 3 prong, and results are as follows:

• 100 - 0
• 200 - .3
• 300 - .8
• 400 - 1.4

A mild deviation from the Kestrel, could also have to do with some of the mild wind coming in as well during this part of the test.

Now, I've never had suppressed values deviate this much from either the Kestrel estimations, or unsuppressed before. Some deviation, sure, but normally it is incredibly mild, YMMV. I inspected the RC2, no strikes, no sign of physical disturbance. I setup a camera with mic down range at ~350 to listen to the round, the volume from the suppressed round passing by was noticeably louder than the unsuppressed round passing by, leading me to believe that what is going on here is that the can is causing a good degree of instability. The theorized instability, however, is not great enough to the point where it is key holing or anything, results are quite repeatable and consistent during the suppressed shots, so it's not at the point of tumbling.

Note: This can functions fine when it is used for its intended purpose of course, functions well with 308/7.62, no issues with heavy trajectory deviations.