FN FNAR 308 Tactical ----- good buys

[Majer]

What ammo were you using? might want to try something different.

[alfsauve]

That will be the next trip.    All I had was the 149gr stuff.  A variety for sure next time.   

[Solus]

Do you know the rifling twist rate?

[tombogan03884]

One of the ammo companies, I THINK it was Remington, had a function on their website where you entered your barrel length and rifling twist and it would tell you the best bullet weight to use.
It was something I heard about a couple years ago.

[Solus]

One of the ammo companies, I THINK it was Remington, had a function on their website where you entered your barrel length and rifling twist and it would tell you the best bullet weight to use.
It was something I heard about a couple years ago.

That is very true. 

Bullet weight determines bullet length and rifling twist is has a large impact on stabilizing a bullet of a given length.





 

[Sponsor]

[alfsauve]

Thanks all for the suggestions. 

I will gather a number of different bullet weights and loads for the next trip with the .308s.   It'll be a couple weeks before I take them out to the range.    I have other projects lined up at the range for at least the rest of August.   

[Solus]

Sinclair’s Simple Twist Rate Measurement Method
If are unsure of the twist rate of the barrel, you can measure it yourself in a couple of minutes. You need a good cleaning rod with a rotating handle and a jag with a fairly tight fitting patch. Utilize a rod guide if you are accessing the barrel through the breech or a muzzle guide if you are going to come in from the muzzle end. Make sure the rod rotates freely in the handle under load. Start the patch into the barrel for a few inches and then stop. Put a piece of tape at the back of the rod by the handle (like a flag) or mark the rod in some way. Measure how much of the rod is still protruding from the rod guide. You can either measure from the rod guide or muzzle guide back to the flag or to a spot on the handle. Next, continue to push the rod in until the mark or tape flag has made one complete revolution. Re-measure the amount of rod that is left sticking out of the barrel. Use the same reference marks as you did on the first measurement. Next, subtract this measurement from the first measurement. This number is the twist rate. For example, if the rod has 24 inches remaining at the start and 16 inches remain after making one revolution, you have 8 inches of travel, thus a 1:8 twist barrel.

http://www.accurateshooter.com/technical-articles/gunsmithing/how-to-determine-barrel-twist-rate/

[tombogan03884]

Simple effective and a cool idea.😁

[Solus]

when I've measured twist, I push the rod in from the muzzle into the chamber and then pull back towards the muzzle an inch or two.  Then I mark the rod at the muzzle and continue pulling until the mark is in the same position...then I just have to measure how much new rod was exposed....eliminate the math.

Don't know of any downside to doing it that way, but someone might have one?

[billt]

Alf,

The FNAR in .308 has a 1 in 12" twist. I've read all over the place these guns are very capable of shooting MOA or better. They're most likely to do that with Federal Gold Medal which utilizes the Sierra 168 Gr. Matchking Bullet.

These guns are basically Browning BAR's that accept a large capacity, detachable box magazine. That rifle has always been a decent shooter. If you haven't tried it yet, I would for certain pick up a couple boxes of the Federal Gold Medal stuff, along with the Black Hills equivalent of the same stuff. Go on a nice calm day, and I'll bet those groups will tighten up considerably.

There is one other thing I would suggest, if the Gold Medal factory ammo doesn't do the trick. Make up some handloads using the Sierra Matchking in both 168 Gr., and 155Gr. Go with 42.0 grains of Varget for both. Use Match Primers, and trim the brass to minimum overall length. Seat the bullets no more than .020 off the lands, and DO NOT CRIMP. Single load each round directly into the chamber, letting the action slam shut good and tight on each round. Take time prepping the cases, being sure to inside chamfer the neck, etc.

Varget has a good mid range burn rate, and 42.0 Gr. of it is perfect for both of my Springfield M1-A's. Your FNAR should swallow them without a hiccup as well. This load will cycle your action without damaging your op-rod. In fact, it's listed as a load for the M1-A and M-14 Service Rifle. Semi auto .308's do not like slow burning powders, because they put too much stress on the action, by allowing it to cycle while it is still under too much pressure. This load also shoots one hole groups at 100 yards with both of my Savage bolt action .308's. A Model 10-FP, and a Model 12FT/R. So I know they're good to go with a 1 in 10" twist which both of those rifles have.

Seeing as your rifle has a 1 in 12" twist, keep everything the same as I described, except drop down to the 155 Gr. Sierra Matchking. It's a bit shorter, and should improve accuracy in that slower twist rate barrel. It has the same ogive as the 168 Gr. Matchking, so you shouldn't have to adjust your seating die to hold the same cartridge O.A.L. Let me know what washes out. I'm guessing that gun will tighten up like a virgin on prom night.