Using 175 SMKs in 1:12 twist?


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Fatelvis
June 4, 2003, 01:07 PM
I was wondering does anyone use 30 cal, 175 SMKs in a 1:12" twist barrel, with success? I like what I hear about its ability to buck wind better than the 168, and its 1000 yd performance, but will 1:12" stablize it? The rifle is a Rem 700 VLS. Thanks!

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Delmar
June 4, 2003, 01:17 PM
Let me know if you try it-I have a VS in 308, 1:12 twist, and it likes hornady 180 grain spire points. Don't know what the streamlined shape of an SMK will do through the rifling, but I guess there is one way to find out!

Steve Smith
June 4, 2003, 01:22 PM
Werd is that they will....

























Robble robble robble!

1 way to find out.

Fatelvis
June 4, 2003, 03:39 PM
Im going to risk the $18 and try it! I can always use them in my M1A. Ill let you know how they group.

JStordahl
June 5, 2003, 12:38 AM
Fatelvis: They should work fine.......they are the accepted projectile for long range .308s. I get nice tight groups with a Winchester using 44.5 grs Varget and BR2 CCI primers with fireformed Lapua brass. I s'pose a few wouldn't hurt, but using them in the M1A is not recommended due to the heavier recoil factor on the op rod or some such thing. Good luck. :D

dakotasin
June 5, 2003, 02:05 AM
agreed.

the vls will stabilize 'em. i've had no problem stabilizing 180's for that matter. thought i might try 190's, but the 308's little case begins shedding velocity if you go much over 175 grain bullets...

echo3mike
June 5, 2003, 07:44 AM
They work just fine. The 168gr SMK seems to give slightly better groups at the shorter ranges...popular theory is that the 175's don't stabilize for a bit, which means you might have to get out to >300 yds before you start to see any benefit. Shooting the 168gr at 1K can be done but it's a big chunk of work and skill to pull off.

I second JStordahl's loading of the 175gr behind 44.5gr Varget / CCI BR-2. Loads between 42.8 and 45.0gr of Varget have worked exceptionally well in a large number of .308 rifles, especially when using the CCI BR-2 primers. This occurs regardless of brass or seating depth.

S.

Steve Smith
June 5, 2003, 09:42 AM
JStordahl, the 175's are fine in an M1A.

However, the 1:12 twist in an M1A could cause some instability, I have spoken to a few that said they'd had problems. Mine has a 1:11" (on the faster side of that actually) and it did ok with them. I wonder if you guys had better luck with 1:12's because you were pushing them faster than you can from a gas gun?

MLC
June 5, 2003, 03:53 PM
I'm waiting for a break in the rain to go to the range and try out some 175g loads out of my LTR. I used IMR 4064 for my experiment. I plan on shooting out to 500 yards.

Grump
June 5, 2003, 07:14 PM
Since the 173-gr M118 round's bullet was okay in the M14, I doubt you'll really have port pressure problems loading 175 MKs to safe velocities using reasonable powders. Isn't the M118LR G.I. round just the old 7.62 match number substituting the 175 MK anyway?

Stability *might* be marginally affected since the 175 is a bit longer, but I'd go with actual experience. If you find it unacceptable to go from .6 MOA to .75 or even .875 MOA, then maybe you shouldn't try the 175s in a 1:12 barrel of 22 inches.

And what's the twist on the Army and USMC sniper bolt guns?

Archie
June 6, 2003, 12:48 AM
I've been shooting 174 grain military HPBT in my VLS and they do just fine.

IMR 4895 to about 2400 f/s and they group half an inch or so at 100. VV 550 will get them up to 2600 and still tightly clustered.

MLC
June 9, 2003, 01:43 AM
I made it to the range today and after a bit of warmup threw some rounds downrange at the 500 yard mark.
I have a Rem 700 LTR lightened trigger and GA precision bolt knob, but otherwise stock.
I was using 42.5 grains of IMR 4064 with 175 grain SMK's,
fire formed and necksized Fed brass with 210M primers.
I only have a 6x40 Springfield scope with the Springfield rangefinding reticle on my rifle so click adjustments weren't a "must".
http://www.swfa.com/riflescopes/springfield/223ret.gif
I took some shots to get an idea of my point of impact then corrected elavation, shot a few groups, corrected etc.
The plate was an orange blur under the tiny 500 yard X. I shot four groups(of 3 since i was sharing ammo with a buddy) total aiming at COM on two blaze orange 9" paper plates.
getting on target
1st group: 3.105" two 2.21" apart
2nd group: 5.7" two 1.62" apart
both solid groups on plate
3rd group: 4.2" two 1.86" apart
4th group( fully zeroed): 3.46" two .796" apart(called that flyer
:) )
I can't say these groups are 1K yard quality but it is a step in the right direction. I haven't shot at over 100 yards since the fall if not summer. All the holes were nice and round so they were stable at 500 out of my 1:12 twist. Sadly my load I decided to use on Whitetail(150g NBT) showed its true colors at 200 and I am going to look for a new one.
(edited with correct CTC measurements )

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