Comparing velocity b/t the opposite ends of the AR practical barrel length spectrum

AR/M4 AR Technical Discussion
1

Thanks slomo.

2

Good info. 18" looks like it has a suppressor mount, might be interesting to track suppressed/unsuppressed with the same ammo.

Are those just photos of the chronograph screen? Might also read better if you dumped all the info into a single spreadsheet. Google Docs is good for that.

3

Great stuff, Trident. Man, I wish I had the time and means to get to play as much as you do! :smiley:

4

Man I love when you guys get into something like this. Always so informative!

I think Rob is onto something with the suppressed vs. un-suppressed. That would be interesting to see for sure.

Keep up the great work.

5

FNG here, but thanks, trying to learn all i can before i start my first build. Seeing how different barrel lengths and bullet weights work, will go a long way in making my choice.

6

Is the Privi 55 grn a 5.56 load? Its cookin along pretty good out of the SBR.

7

Trident,

Thank you for providing these data. Did you happen to get any chrono data for the 77 gr SMK?

8

IMHO, Trident, you might want to try this with only Mk. 262, Mk. 318 clone, and M855, with the muzzle devices removed.

I appreciate the numbers given, but I don’t think you used the most scientific method you could have.

I don’t mean to nitpick though.

On a side note, that Privi 55 gr. stuff is getting really good numbers out of that 10.5’'.

I’ve been interested a 5.56N loading optimized for short barrels.

9

I own two dinosaurs and I didn’t even know it! C’mon, when the 20" M16 sees continuing use with the USMC and Canada, and some US Army use along with enormous recent past use, I think a 20" barrel can be considered practical. I would concede that longer than 20" is getting into special purposes or hunting uses.

Otherwise the data is very interesting and I always like seeing comparisons like this.

10

Glad to see this particular data. I’d be interested to see some 75 grain loads (as that’s my defensive ammo of choice) especially from the 10.5" since I just picked up an LMT MK18 upper.

Now these are the types of tests that seem to have merit and is just good info for everyone.

11

Rob, I think you have a little fetish for spreadsheets :stuck_out_tongue:

Nice work Trident. I would also like to see the 75gr stuff out of the 10.5"…especially TAP T2 if you don’t mind.