Best bullet for caliber and twist?

[sliverflinger]

I'm not a total nubie to hand loading, been at it for thirty ? years. I have never run into this problem before. My new AR upper is a 1-7 twist and really doesn't like 55 gr. bullets. I've run into this before but on a much smaller scale. I guess my question is , what is the optimum bullet wt. for a 223 bullet in a 1in 7 twist.

[Lycanthrope]

I'm not a total nubie to hand loading, been at it for thirty ? years. I have never run into this problem before. My new AR upper is a 1-7 twist and really doesn't like 55 gr. bullets. I've run into this before but on a much smaller scale. I guess my question is , what is the optimum bullet wt. for a 223 bullet in a 1in 7 twist.

Somewhere around 80 gr. Mine love the 77gr Nosler Custom Competitions. I had two gusnt at ran those under half an inch. In contrast they shot 55gr bullets over 2 moa.......depending on the brand.


LycanMidwayhastheNoslersthrope

[Mr White]

55s are at the very low end of what a 1:7 will shoot well. I have a 1:8 and it loves the Sierra 60 gr Varmiters, but my groups start to open up with 55s. A 1:7 will shoot heavier bullets very well. 62s up thru 80 and 90 gr. The M16A2 has a 1:7 barrel and the 62 gr SS109s are made for that gun. If you can find some of those, they wouldbe a good plinking bullet for you.

I'd also try a some 69 gr Matchkings or some 75 grain A-Maxes. I doubt you'll be disappointed with how they shoot from your gun. Not the cheapest bullets to plink with but if you're looking for tiny little groups, they'll make you happy.

[Lycanthrope]

Yeah, but the SS 109 is steel core, right? That makes it a longer bullet than a typical 62gr lead core bullet since steel is not as dense as lead. It's actually bullet length that is sensitive to twist rate and 62gr lead core bullets aren't going to shoot as well so it's important to mention that.

Lycansidenotethrope

[sliverflinger]

Thanks guys! I'll try to pick up a couple of different bullets and see what happens. The only real problem I can see , is that they are getting sort of long. To keep them under mag length it looks like I'll be seating deep. That's going to take powder space out of a case that doesn't look all that roomy. It appears that you could reach a point of diminishing return rather quickly. I load 6.5 grendel so I'm used to compression loads but the 556 is a whole new ballgame. Again thanks for your help.

[notenoughguns]

I think the deeper throat on the 1x7 twist barrel may also have an effect on the accuracy so ogive may play a part in finding the right slug .

[Lycanthrope]

I think the deeper throat on the 1x7 twist barrel may also have an effect on the accuracy so ogive may play a part in finding the right slug .

That's a new one to me. 1:7 has more freebore than 1:9?

Lycancuriousthrope

[notenoughguns]

Free bore / throat Kind of the same thing , no ?

[Lycanthrope]

Free bore / throat Kind of the same thing , no ?

Yeah, but both are the same chamber so why a different freebore for another twist rate? Never saw that.

Lycan?thrope

[notenoughguns]

Had something to do with full auto I was told .