Hi fellas, sorry I haven't been with you much lately, been doing a lot of ice fishing. Anyway, I built an XM16E1 recently and it has a 1in 12 twist 20" barell. I'm thinking that 55grn bullets should be light enough to stabilize in this barrel. I can't find much for refernces concerning this setup. Can you fellas give me a few ideas to start with? Thanks

Here is a picture or two of the new rifle.


The only parts that aren't correct NOS 1968 are, the lower reciever and a few of the trigger group and pins.

55-grain bullets should do just fine in that twist rate since they shoot well in my 22/250s with 1 in 14 twists. You might even get away with 60-grain if you really wanted to. In .223 I have had best luck with powders like TAC, H322, AA 2015 and AA 2200 (DATA), though the 2200 is pretty hard to find now. TAC may well be your best choice since it is supposed to contain a copper-fouling inhibitor and is temperature neutral (temperature doesn't affect velocity). Ball (spherical) powders meter easier and many times are more consistent.

Good luck and let us know what you work out.

Thank you. I've got lot's of load test data from rounds I've shot through 1 in 9 twist barrels, I look forward to using the data I can glean from you guys.

I always start from the assumption that the starting (and max) loads can best be taken from the various loading manuals.

55 grain bullets should shoot fine in the 1-in-12" twist, that's what it was designed for (According to the Speer #14).

If you've already loaded for ARs you probably already know this but it's something I only learned in the last year or so...

Consider the pressure curve for the powder you pick. The pressure at the gas port is supposed to be within a certain range for proper operation of the ARs. Too high is hard on the action and too low may not function correctly.

Yes Sir, I do the same thing. I was hoping that someone had worked up some loads for specifically the M16 barrel. I think that the pencil barrelled M16 would have quite different barrel harmonics than a heavier 1in12 bolt gun barrel, or most others. I see a lot of info for the AR15 platform, but none for the M16 barreled rifles.I realize this is not a match rifle, I just want to see what it can do. Sometimes somebody else's input that has been there can save a fella a lot of experimenting. Thanks

52 grainers work well too. You are limited to magazine length so OAL and jump will not be as big an issue. I would go with W748, RL-15 or Varget and load some up. I have a buddy that load IMR 4064 into an AR. God bless him for fitting that long stick powder into that case but he has a real fine load in a 68 HPBT for an 8 twist.

I'm definitely going to try the 52grn'ers and the 55's. I'll do a test and let you guys know what came out on top.

I bet that you can get some load help from our friends at AR15.com.

I kind of like Hornady's 60gr soft point over 26gr of RL 15. That gives me about a .625 - .75 group at 100 yards and thats with a cheap Rossi single shot.

I have played a bit with .223s,and have found that for a 1in 12 bbl I have had excellent results with sierra 50 gr blitz bullets over 25 gr of IMR4895,and esspecially on an ar I used 52 gr hpbt match sierras over 25 gr of IMR 4895-these loads accounted for many jackrabbits and a couple coyotes out to 250 yds,in a M-16a1!

26.0gr H335 under a Hornady 40gr V-Max in Winchester brass, and Winchester Small rifle primers.
The brass is cleaned, trimmed, primer pockets are uniformed and flash holes deburred.
This load delivers a .5" group from a Bushmaster Varminter AR.

Here's mine:

Bullet Speer SP
BulletWeight 55 grs
Powder Hodgdon H4895
PowderWeight 25.5 grs
Primer Winchester SR
Brass Make Winchester

I would hazzard to say that 52Gr bullets such as the MATCH type bullets would be about the best for this rate of twist. Ditto on the pressure curve as well. However if it does not bother you to load one round at a time then I would not be to quick to rule out any loads. But watch the loads in Mil-Spec cases that can cause a big problem with over-loaded cases than a .223Rem case will. Basically you can use .223 in a .5.56NATo but not a NATO in a .223. I have heard mixed on case thickness but would say better safe than sorry. I, believe; that the recommended way to start is to drop something 10 percent from starting on a commercial case and work up from there.

By the way, thanks for the load on the 40Gr's from the Bushy Varminter.
Dad has one I load for.

No problem Arron.