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View Full Version : 77 grains on a 1:9 twist barrel - 16" upper


tagacali
05-31-2011, 5:56 PM
Would this work out fine or 63 grains for the most is ideal for this barrel? Thanks

dieselpower
05-31-2011, 5:57 PM
http://i655.photobucket.com/albums/uu272/Wiringguy/223and556twistgraphed.png

killshot44
05-31-2011, 6:00 PM
For the best accuracy 77 is pushing it, especially in a short barrel.

Groups stank with them and 75s weren't much better. The best results are with 69gr SMKs in my 1/9s. Of course, the 52/55 grainers work well, too.

OutkastSL
05-31-2011, 6:04 PM
damn diesel, you always have the coolest most informative graphs.

Knife Edge
05-31-2011, 6:27 PM
For the best accuracy 77 is pushing it, especially in a short barrel.

Groups stank with them and 75s weren't much better. The best results are with 69gr SMKs in my 1/9s. Of course, the 52/55 grainers work well, too.

I'm digging the 69g in my 24". Haven't explored the 40-50g range, but I'm very happy with 1/2 MOA average.

Jonathan Doe
05-31-2011, 8:14 PM
This is what my RRA 26" Varmint upper with 1-8" twist did with Berger 77 grain bullets at 100 yards, 5 shots. Other than one flier, it was very nice.

http://i454.photobucket.com/albums/qq263/5topgun/Targets/DSC_0005Large.jpg

blazeaglory
05-31-2011, 9:47 PM
This is what my RRA 26" Varmint upper with 1-8" twist did with Berger 77 grain bullets at 100 yards, 5 shots. Other than one flier, it was very nice.

http://i454.photobucket.com/albums/qq263/5topgun/Targets/DSC_0005Large.jpg

nice! almost shot martin sheen!

Dreaded Claymore
05-31-2011, 9:51 PM
That's a really sweet graphic, Dieselpower. Thank you!

NYY
05-31-2011, 10:17 PM
http://i655.photobucket.com/albums/uu272/Wiringguy/223and556twistgraphed.png

this is really helpful. I've always been curious as well. Thanks!

Ruiner
05-31-2011, 10:20 PM
http://i655.photobucket.com/albums/uu272/Wiringguy/223and556twistgraphed.png

It's really a shame they don't make high quality chrome lined barrels in 1/8.

Bigbird19
05-31-2011, 11:07 PM
Suggestions on good 62grain non magnetic ammo hah

killshot44
05-31-2011, 11:09 PM
Handloads....

dieselpower
05-31-2011, 11:10 PM
It's really a shame they don't make high quality chrome lined barrels in 1/8.

The 1:8 is an accuracy build. Chrome lining subtracts accuracy, as does button rifling.

If you want extreme accuracy, get a SS 1:8 triple lapped barrel from ArmaLite or Noveske.
http://www.armalite.com/ItemForm.aspx?item=U15A2NM&Category=bce7fa68-373e-4afc-b00e-63fe2c75d131

23 Blast
06-01-2011, 6:12 AM
Pretty cool stuff. Just curious from those who know - what's the typical twist rate of a bolt-action varmint rifle in .223?

goodlookin1
06-01-2011, 6:32 AM
I tested my 1/9" chrome lined barrel with handloads using a wide variety of bullets: 55 HDY TAP, 55 FMJ, 62 FMJ, 68 HDY HPBT, 69 MTKG, 75 HDY HPBT, 77 MTKG, Winchester .223 55, Winchester 5.56 62, PMC 55, XM193 55, Remington 45 GR, etc etc. Do you know what I found?

They were all the same. Didnt make a lick of difference. However, I was just using a 3x magnifier behind an Eotech, so it wasnt a super precise optic setup.

If you're shooting matches and need that accuracy, yes....the twist rate/length of bullet will matter. Not too terribly much, but it will....Especially the further out you go. But if you're talking a military grade MOA+ shooter, then it doesnt matter. Any of the current crop of barrels will do just fine. And this is what most people are going for, your average every day plinker. Just get a 1/8 or 1/9 and be done with it. You cant shoot more than 80 GR bullets anyway without being forced into single shot mode (they are too long and wont fit in a magazine body), so for me, the 1/8 or 1/9 works out the best.

Always remember: The twist rate is not the end-all, be-all of accuracy.....the quality of the barrel matters much, much more.

gun505
06-01-2011, 9:25 AM
good info, Its hard to find the heavier loads that are not over priced.have a 1.7

dieselpower
06-01-2011, 9:46 AM
good info, Its hard to find the heavier loads that are not over priced.have a 1.7

There is nothing wrong with shooting 55gr out of a 1:7...its just not as accurate as the heavy stuff. Most shooters will not see the difference.

Just spend the money and keep the ammo on hand...dont use it, Its an investment. Buy the cheaper 55gr FMJ for practice and fun, buy the 55gr JHP for hunting small game, general stuff and buy the expensive defensive ammo to store away.

The long range aspect of 77gr with 1:9 as it pertains to fragmentation against a human is an issue, and one I don't care about. I shoot 1:9 and have 77gr for defensive loads. Its a short coming I know about and disregard as it is something I will never see. I am not going to be taking a shot at a threat 300 yards away from me. No LEO would expect that situation either.

Even the Hollywood shoot out, if the LEO had 1:9 with 77gr ammo it would have been fine. We are talking threats 3-6 FOOTBALL FIELDS away to start caring about 1:7 over 1:9 and 55gr vs 77gr fragmentation on a human beings body.

Believe me, your threat is 150 yards away (a block or so) and you put a 77gr or a 55gr defensive ammo into their chest, the twist isn't going to matter...with either or any, the result will be the same....massive soft tissue trauma, blood loss and death if no medical attention within 3 minutes.