5,56x45 Nato, which twist rate ?

[lani]

hey

Anybody know which twist rate is good for the 62 gr. steelcore nato round ?

is it possible to obtain good precision with this round ?

Im not speaking about BR precsision but under 1 MOA at a 100m ?

best regards

Lasse Nielsen, Dennmark

 

[stgw77]

Hi,
62 grs military bullets are much longer than 55 grains heavy, so I think you should need 1:9" or maybe marginal 1:10" twist (instead of 1:12" twist for 55s). In my Steyr AUG (with 9" twist) they work just fine, with one MOA precision or sometimes even better.
BR,
Klemen from Slovenia

 

[1000yardstare]

Bought 500 62 gr NATOs from a Canadian surplus dealer in the 1980`s. Back then was using a 9 twist McGowen barrel throated for 69 gr Sierra SMKs on a trued 722 action.

Load for the 62 NATOs was 23 gr AA2460. Chronod at 2930 fps.

Generally put 5 shots into an inch at 100 metres but would get a big flyer now and then. Some bullets were considerably longer or shorter than the average length which probably accounts for the fliers.

 

[cmillard]

a 9" twist will do just fine for that bullet. i shot many of those bullets and found them to be fairly accurate. the one thing i didn't like about them was when sorting them by bearing length (a waste of time for these bullets), they were all over the map and varied greatly.

 

[Laurie]

1-10" is marginal. 1-9" or anything faster is ideal. The NATO rifle barrel spec is 1-7" but you don't need that for the ball cartridge SS109 pattern bullet.

Quality varies greatly according to the manufacturer, then within that by lot. Remember they have a steel penetrator core above a lead rear core and below a large tip cavity inside a stepped jacket. This makes it a much more complex bullet than a hollow-point BT match design. Then there is the issue of swaging the steel penetrators from steel wire. I'm told it's like a machine-gun spitting hundreds out a minute into a bin with the swaging dies wearing out within a shift. Think about the accuracy of that sub-core's dimensions between new and worn out dies - it's the sort of variation that gives a manufacturer of quality bullets sleepless nights. Then throw in a government contract price that most people would starve on and a finished ammuinition precision (grouping) specification that has little in common with what most people on this forum are trying to achieve.

If you think I'm trying to point you in a particular direction you're right! Personally, I wouldn't waste barrel life and powder in shooting them. I've tried and gave the unused majority away (free!). I do know of one group who say they can be preferable to handloads with SMKs - Service and Practical Rifle shooters. As well as shooting at 'advancing hun' (Fig 11 over here in the UK) human torso size targets, the large dispersion of the 62gn SS109 pattern slugs makes hits easier to spot, so the shooter can be assured of being on target. With MatchKings or similar they may form a relatively tight group in a black area of the mottled target colour and don't show up.

Laurie,
York, England

 

[people]

I also second the 1:9 twist. Granted if you are going to buy a new tube you could get a 1:8 and then shoot 80gr bullets if you wanted. A few years back I got some US pull down SS109 bullets and they shoot fine. If you want to sort them they will shoot much better. I sorted a batch to get bullets all the same weight and bearing length. They shot pretty well. I shot almost a full mag and I was able to get almost .5 inch group out of them. I had a few flyers that bumped it to just over .5 inch. With that being said there was a lot of work to get that. I personally think that the 55gr bullets shoot better with far less sorting but that is just me.

 

[stanlyonjr]

I have a 16" 1:7 barrel that spits out 62gr 855's very well at 100 yards. 1 inch groups without much effort. Just make sure your barrel can handle the hotter 5.56 ammo!

Aim for the X

Stan