reloader 15 vs AR COMP for 223/556 AR 16" barrel

[RustyKnifeUSMC]

For the lighter bullets ... H335 or TAC.
Heavier stuff ... IMR 8208 XBR.

As mentioned, AR Comp is the "temperature insensitive" verision of RE15. Which is excellent for 68 grains and heavier.

[Kaiser Mike]

just did some Re15 for 75gr hornady bthp match. 24gr at mag length and cci 450 primers.
sub moa.

This was out of my new 18" SPR (PSA build).

[T2C]

Reloder 15 is a good all round powder for High Power shooters. I am not surprised by your results.

[bb223]

Between those two, I would use the AR Comp just because I hate how temperature sensitive RL15 is.

If I had another choice though, H4895 is what I would use. I've never used IMR4895 so I can't comment.

But 23.5gr H4895, CCI450, and a 77 Nosler has been the best shooting heavy OTM I've ever loaded. The 75gr Hornady with the same primer and charge weight shoots pretty good too but the Nosler has the edge.

I get 2650ish from a 16" Colt.

[terraMODA]

Seeing as AR Comp is also a double-base powder (but spherical vs extruded) I don't see how it could possibly be any less temperature sensitive.

Ar-Comp is a stick/extruded powder just like RL-15. I like it in my 16" 308.
I weigh each charge so not worried about it metering poorly, which as a stick powder, it tends to do.

[jaholder]

Between the 2 powders, I'd try AR Comp. It's a bit faster than RL15 and Alliant's data shows some pretty impressive velocities using 55 grain bullets.

As far as RL15 temperature sensitivity, I've been using RL15 for both .308 and .223 for years in temperatures ranging from below freezing to 105 in the shade. FWIW I've not seen RL15 show any more or less temp stability than any of the other stick powders, exceptions being Varget and some of the other ADI made stuff Hodgdon markets under their Extreme line. as always YMMV.