Performance of SMK HPBT 190 gr

[Praire Dog]

Good morning,

I'm thinking of the possibility to test this bullets, the Sierra HPBT 190 gr in my 300WM rifle for long range shooting. What experience do you have with their accuracy? What is the maximum distance you have shot with it?

Thanks!

 

[sable tireur]

This is the bullet originally loaded by Federal for the U.S. military .300 Win. Mag. Bullet performance was never in question although the Re-22 used had occasional pressure excursions. The Sierra 190 gr. HPBT was a mainstay until the military required a new load for longer ranges, when the Sierra 220 gr. HPBT came into play.

However, not satisfied with that level of performance, and with change of legal opinion allowing snipers the ability to use modern match projectiles without committing a war crime, NSWC Crane continued to develop a solution and came up with Mk248 Mod0 built around the 190gr Sierra Match King.


Mk248 Mod 0 300 Win Mag (duplication load from a source I trust)
Bullet: 190gr SMK
Brass: Federal Brass
Powder: RL-22 powder 73.5 grains
Bullet: SMK 190 3.465″ OAL
Primer: Federal 215M primer
Velocity = 2,950 fps
Accuracy standard, no greater than 6″ extreme spread at 600 yards.
*NOTE, THIS DATA IS HOT, ALWAYS BACK OFF 10% AND WORK UP IN YOUR RIFLE.

For many years, military snipers utilized weapons like the MK 13 series or M2010 Enhanced Sniper Rifle, firing "A191" Department of Defense Identification Code ammunition, to achieve a "government-published" effective range engagements of 1,200 yards.


An ammunition performance challenge emerged in the 2000 to 2010 timeframe reflecting a new user requirement that called for an effective range of 1,500 yards with a decrease in the effect of wind drift on the projectile.


Ballistic experimentation with several different projectile options led to a product improved design that — among other things — replaced the 190-grain projectile in the A191 design with a heavier 220-grain Sierra MatchKing bullet, with overall results that met the new requirements.


The two bullets also led to sub-designations of MK 248 MOD 1 and MK 248 MOD 0, with the MOD 1 compared to the A191 with some improvements and the MOD 0 reflecting the heavier bullet enhancements.


The MOD 1 has historically been viewed as an Army load, while the MOD 0 has historically been viewed as a Navy load.

Enjoy!

 

[105Coues]

Excellent info. Thanks.

 

[Praire Dog]

Thank you for your excellent answer! I always wanted to try the HPBT 230gr, but due to stability reasons it requires 1:8 twist and it was impossible for me to find a 300WM with such twist.
I've never tried HPBT 220 gr either. Do you think that 1:10 twist is enough? It doesn't make sense to go to very high ballistic coefficient bullets if your rifle can't make them stable. Because that also reduces the effective ballistic coefficient.

 

[sable tireur]

I've never tried HPBT 220 gr either. Do you think that 1:10 twist is enough? It doesn't make sense to go to very high ballistic coefficient bullets if your rifle can't make them stable. Because that also reduces the effective ballistic coefficient.

Using the Berger Stability calculator, a1:10" twist and 2,850 fps. the 220 SMK is completely stable:

 

[Bravo 4]

Been shooting the M2010 (Army) and A191 ammo (190 grain SMK, .300 WinMag) for as long as it's been out. To give you an idea (and not counting the years spent in a Sniper Section), the past 4 years I've ran a Sniper School we draw 30,000 rounds of the stuff (and 30,000 rounds of 7.62x51 M118LR) per class. I have shot the stuff well over a mile. My opinion is that it is an ok bullet for long range target, but there are better options. Many more modern designed bullets will have a higher BC, even the newer 169 grain SMK has basically the same BC and is probably even less expensive to purchase. I will say that I don't think I've ever fired (or seen fired) a rifle that didn't group them decently.
If they are abundant (and cheap) where you from, then I would grab a bunch of them and go shoot! If they are as scarce as everything else, they wouldn't be my first choice.

 

[Praire Dog]

Been shooting the M2010 (Army) and A191 ammo (190 grain SMK, .300 WinMag) for as long as it's been out. To give you an idea (and not counting the years spent in a Sniper Section), the past 4 years I've ran a Sniper School we draw 30,000 rounds of the stuff (and 30,000 rounds of 7.62x51 M118LR) per class. I have shot the stuff well over a mile. My opinion is that it is an ok bullet for long range target, but there are better options. Many more modern designed bullets will have a higher BC, even the newer 169 grain SMK has basically the same BC and is probably even less expensive to purchase. I will say that I don't think I've ever fired (or seen fired) a rifle that didn't group them decently.
If they are abundant (and cheap) where you from, then I would grab a bunch of them and go shoot! If they are as scarce as everything else, they wouldn't be my first choice.

That is a lot of stuff my friend. Sounds like you are really proficient with it. Any other suggestions regarding bullets to shoot 1 mile or above with the 300WM 1:10?

 

[Bravo 4]

There are several what I would label conventional bullets (cup-n-core) from Berger and Hornady that are in the 190+grain category that will shoot from a 1-10 twist. There are also several "specialty" bullets on the market too. Don't know what you have available in your area (Spain?).

 

[Praire Dog]

My home country is Spain but now I'm in Switzerland, maybe that makes the selection of bigger. I guess I can access to all the usual bullet. Maybe some of the "specials" you say. What bullet would you use for a mile with the 1:10?

 

[ARlife4me]

Thank you for your excellent answer! I always wanted to try the HPBT 230gr, but due to stability reasons it requires 1:8 twist and it was impossible for me to find a 300WM with such twist.
I've never tried HPBT 220 gr either. Do you think that 1:10 twist is enough? It doesn't make sense to go to very high ballistic coefficient bullets if your rifle can't make them stable. Because that also reduces the effective ballistic coefficient.

And yet the 240 requires less twist is why I went that way in 240smk.

 

[ARlife4me]

Berger 210 class is a 10 twist choice and maybe their 215's. Go on Berger site and use resource at top of page (I think that's where it is)? Select range bullet, twist and velocity on your inputs. They have a stability calculator and can print range cards.

 

[Chas1]

Excellent info. Thanks.

+1

 

[Echo Charlie]

Use smk190 (because I got inexpensive a couple thousands several years ago) on a Sendero 300WM 26" barrel 1 in 10" twist but prefer Berger 220 grain Long Range Hybrid Target. Load them on Lapua brass 73.4 grain of VV N565 and Federal GM215M. Gives around 2800fps and groups 5 shots in less than moa. Problem now is to get more of those bullets

 

[Calvin45]

My home country is Spain but now I'm in Switzerland, maybe that makes the selection of bigger. I guess I can access to all the usual bullet. Maybe some of the "specials" you say. What bullet would you use for a mile with the 1:10?

Hi there!

I can attest from what my personal experience that hornady's 225 grain eld match stabilizes great from my 10 twist .300 win mag. Hornady's Doppler BC number of .777 was determined from a 10 twist with this bullet, number goes up a bit from a faster twist but .77 is hard to beat if your rifle likes them, which mine does.

Another serious contender is the sierra 200 grain smk BUT there are two different 200 grain smks…I'm talking about the newer one.

PART NUMBER 2231

has a bc of .71 at over 2000 fps, maybe a tad lower from a 10 twist

Sierra explicitly does state 1:9 twist or faster. HOWEVER, I emailed them directly to inquire about their viability in my rifle and they actually replied (very quickly too) that the 1:9 twist requirement ensure stability at .308 Winchester velocity at sea level. They assured me that at full power 300 win mag velocity at my 1100 feet elevation (not that much) I would have zero stability issues

That's a great bc to weight ratio, and with the very short bearing surface and subsequent lower pressure 3000 feet per second is very possible. I actually just bought some but have not yet tested them

I drive my 225 elds to 2760 at the moment but will be working up a new load soon NOW THAT THEY WENT AND DISCONTINUED MY BELOVED IMR 8133

Food for thought, hope it helps, and hello from Saskatchewan, Canada