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16" 1:9 Twist stabilize 77gr bullets?


sshog8541

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I'm testing between my Rolling Thunder and the Surefire. The Surefire on my 308 bolt rifle is ridiculously soft.

Surefire and a PRI handguard. Seems like I've seen that setup before (i.e. Taran's rifle) ;).

Rich

Edited by uscbigdawg
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To the OP, there are always "rules" about what bullet will (or won't) spin in a given twist barrel. However, after a TON of rounds through AR's I'll say that while these 'rules' are good guides, in the end, you have to shoot the bullet and twist combo in your rifle. There are way too many variables to simply say something will or won't work simply based on bullet weight and barrel twist rate.

Heck...the upper I just sold to 'maineshootah' will shoot 52's all the way up to 77's and it's a 1:9. Remember too that for 3-Gun you don't need a sub-MOA rifle. Frankly a 2 MOA rifle will generally work for most 3G/MG matches.

Rich

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Would a 55gr bullet driven hard with a faster powder not out perform a 77gr bullet in a questionable twist rate bbl going slower?

sshog8541, a Marine Scout Sniper as your name suggest should know about the 77gr bullets in a 16" AR platform.

If I had a 1/9 twist 16" bbl on an AR and was going to be shooting 400 yards and in, I'd shoot the 52 gr Amax really fast. Good for mil holds, and decent in the wind because of its speed. Accuracy will be there also. My 1/9 shoots them well under MOA.

I don't really see a need to shoot the 77gr unless you plan to go to 600 yards and beyond and need one to feed from the mag. Even then, a 16" bbl would not be my choice since you need the velocity for the 77 to even be effective at distance. More is better in velocity or bbl length, but not in bullet weight, at least not in your application if it is 400 yards and in.

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Would a 55gr bullet driven hard with a faster powder not out perform a 77gr bullet in a questionable twist rate bbl going slower?

sshog8541, a Marine Scout Sniper as your name suggest should know about the 77gr bullets in a 16" AR platform.

If I had a 1/9 twist 16" bbl on an AR and was going to be shooting 400 yards and in, I'd shoot the 52 gr Amax really fast. Good for mil holds, and decent in the wind because of its speed. Accuracy will be there also. My 1/9 shoots them well under MOA.

I don't really see a need to shoot the 77gr unless you plan to go to 600 yards and beyond and need one to feed from the mag. Even then, a 16" bbl would not be my choice since you need the velocity for the 77 to even be effective at distance. More is better in velocity or bbl length, but not in bullet weight, at least not in your application if it is 400 yards and in.

Are primiary weapon system is the M40 which is a .308

In the Marine Corp we shot Green tip 5.56 62gr.

The hole reason iam asking is for 3-gun purpose & knocking steel down at 400+yds. Last year I had trouble knocking the steel down with 55gr

if u want to be a smart ass stay out of the Tread.

GM Open Mouth shooter

-How Copy

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I'm with hog on this one. We'll be shooting the same round through pretty much the exact same rifle at R&R Racing's 3 Gun this year and a couple others. We don't necessarily have the option to bounce around different barrels or rounds. We do have the option (maybe) of going to the Federal Gold Medal 69gr BTHP. We just want to see if the Federal Gold Medal 77gr BTHP will perform the same or close. Just want to make sure we are slamming down that steel out to 400 or maybe further.

Thoughts?

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Nothing smart ass about my response, just good information, and it's worth what you paid for it, which was nothing. You didn't learn anything about M193 or M855 in basic training?

And yes, I am very familiar with the M40A1-3 and the M118LR, but you didn't go through basic training with the M40, you qualified with an AR.

Maybe you should also ask other 3 gunners what they are shooting in 3 gun comps. I know some that shoot 52-55's for all close stuff and have a spare mag loaded with heavier bullets they transition to just for the LR stuff.

The XM 193 55gr .223 milspec ammo is still traveling over 1800fps at 400 yards with more than 400 ft lbs of energy and only 6.4MOA of drop with 5.2MOA of wind.

The 77gr bullet at 2850fps mv is going just over 1900 fps at 400 yards with 626 ft lbs of energy and 7.4 MOA of drop with 3.9MOA of wind.

400ft lbs of energy should nock down any steel it hits if the hit is good. A 9mm with 131pf has less energy at the muzzle, only producing 307 ft lbs.

I'll refrain from posting in your thread anymore, their is no real answer for you original question, and the advice you've been given is sound. ;)

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If your shooting 400 yards plus.. the best choice is the SIE 77gr SMK, in tactical matches, this bullet is lenght tolerant bullet allowing you to load to mag length. Standard load for this bullet is 24.0 - 24.5 grs of Varget, winchester or remington brass, CCI BR primer. (BR primers and Varget are like a loving marriage) Be sure to uniform your primer pockets and flash holes. I highly reconmend using an 8 twist barrel and no slower.. Krieger 7.7 is another good choice in barrels. Plus.. one will get about 7K rounds out of a Krieger barrel. Min length 20 inches.

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SShog,

As others have said but if I was to go out and buy a new barrel and had the 77 grain bullet in mind, without a doubt I would get a 1:8 twist barrel! Now if I already had a 1:9 twist barrel I would just go and test it out...the proof is in the shooting!

See you at the RandR match...

Scott

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Where to begin....

As for light bullets, they DO have a place in 3-Gun. One of the best rifle shooters/3-Gun shooters is Benny Hill of Triangle Shooting Sports and he is well known to use 52gr.'s in a 1:12 barrel screamin' and they will knock down steel at distance. Taran Butler is also known to use them, however, goes heavy (as most do) when there are Larue targets or flashers at distance where you have to activate a flag.

IN GENERAL, 69's are great for 3-Gun and GENERALLY out of a 1:8 they are very happy. My 69gr. SMK load with 24.5-ish grains of Varget, WSR, NO BRASS PREP (it's 3-Gun not Highpower) shoots less than .5 MOA with a couple of .2's and .3's out of my 18" 1:8. That's a freak rifle for a couple of different reasons.

sshog8541 - If you have an AR with a 1:9 barrel use it 'til it's burned out and then go get a 1:8. I can strongly recommend the Oly Arms barrels (yep...really) and the barrels from Sabre Defence. JP also makes an awesome 1:8 barrel (it's what's on the middy pictured above).

As stated above though, ultimately it's going to be what shoots in your rifle. Don't rule out Hornady 75's, but in my experience with Hornady bullets, unless you are CRANKIN' them out of the tube, they drop like a rock. 69 and 77 SMK's will fly better and frankly, a 69 will do everything you need.

Rich

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As others have said, you must try them in your rifle. I have a 20'' 1/9 that don't like 75gr bullets. It shoots 4-5 inches at 100. It shoots around an inch with 55gr. I have another rifle with 20'' 1/7 that will shoot an inch with the same 75gr bullets. Good luck.

Hurley

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  • 4 months later...

I have a 20" Bushmaster (1:9 twist) that will shoot 1" 100yd groups with the 75 Hornaday. But I get a few fliers and occassional not so good groups, so I think it's boarderline. Haven't tried 77s. Also have an 18" POF (1:8) that shoots well with everything I stuff in it.

That said, I haven't seen any steel that can't be dropped with a 55. The only match I've seen with targets over 400 yards is Ironman. Are you guys getting frisky with long range over there in the Tri Cities?

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I don't really see a need to shoot the 77gr unless you plan to go to 600 yards and beyond and need one to feed from the mag. Even then, a 16" bbl would not be my choice since you need the velocity for the 77 to even be effective at distance. More is better in velocity or bbl length, but not in bullet weight, at least not in your application if it is 400 yards and in.

69's and 77's are not a nessesity in 3gun, they are an insurance, the extra edge we look to squeez out. A 55 will do

everything as the previous if you feel your going to "center plug" everything. A low hit on a Larue or an edge hit on

an MGM flasher at 350+ will be much clearer to the RO yelling "hit" with and 69 or higher bullet, that's all !!

To the OP, as everyone else has already stated, go try it. 69 is really going to be enough but more is more right ..

I shoot a 69 SMK out of 20" 1/8 barrel and it does everything including RockyMountain 3gun out to 600yd. My 16"

1/9 gun shot 69's but the groups opened up to 1.5-2.0 MOA. I think with a different powder and some time at the

range I could have closed that up a little bit more ...

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