Getting a NATO chamber to shoot well?

[101stinfantry]

I've had multiple rifles over the years with a NATO chamber 5.56 & 7.62. I have never been able to get any of them to shoot exceptionally well i.e. MOA. Seems like most of them have an over exaggerated leade, for example you can't even get close to the lands in a 5.56 with a 60 gr. bullet w/o it falling out of the case. Now I realize the difference in chambers, and I don't expect .5 MOA from one, but has anyone else done better? I can occasionally come up with a 1.5MOA load, but damn is it frustrating, sometimes it'll even fit in the magazine!

 

[MarinePMI]

Neck tension. Crimp.

Anytime you have a huge bullet jump due to chamber leade, playing with neck tension and/or a factory crimp (ala Lee FCD) is worth exploring. Many a rifles of mine that had military chambers responded very well to either increasing neck tension via a bushing die, or just experimenting with crimp tension. Some rifles went from well over MOA to 1/2 MOA. There's a reason military ammo is crimped, and it isn't just for survivability, it is also for reliable neck tension. Most milspec rifles/MG's have a very long leade/throat to contend with potential over pressure issues (wet ammo, dirty or oily ammo), so a crimp helps by uniforming the neck pull/neck tension consistently across the individual rounds.

Is it optimal for accuracy? In a match grade chamber, probably not. Is it optimal for accuracy in a military/NATO chamber? Probably so. A heavy/strong neck tension can cure a multitude of sins in a sloppy chamber...

 

[MTRecon]

My circa 1980's Colt Sporter II will do MOA @ 100 yards. 20" Nato 1/7 with a wedge to tighten the upper/lower. Using bipod and shooting from a bench.

Haven't tried it with factory ammo...using hand loads with uniformed brass, competition dies, IMI 55 FMJBT and BLC2. Varget works great to.

 

[Codiekfx400]

Try a bullet that is less sensitive to jump such as a 50 gr vmax. Also as MarinePMI said try exploring a crimp.

 

[Onyx Z]

I have a factory M&P15 5.56 NATO chambered 1/9 barrel that shot 77gr handloads to .5 moa. It is doable when loaded to mag length, regardless of jump.

Try XBR with 77gr SMK's and H322 69gr SMK's. They shoot VERY well in every rifle I've tested them in.

 

[101stinfantry]

I've got a Lee Factory Crimp die, I'll give that a try. This particular rifle is a 1-8, 5.56 chambered Ruger American Ranch w/ a 16" barrel. When I ordered it I apparently didn't see that it was a 5.56 chamber. I did get a decent group today with 77 gr. SMKs, and BL-C2, but I haven't been crimping them at all, so I'll give that a go on my next OCW. Thanks guys, this MFer was beginning to piss me off! Lol!

 

[MarinePMI]

Also try XBR as a powder. It seemed to do better with the heavier bullets. BLC2 was okay, but no where near as good as XBR.