SMK 142gn or SMK 140gn for 6.5 x 284??

[1066]

The SMK 142gn 6.5mm bullet seems much more popular for long range target shooting than the SMK 140gn bullet. Is there any reason for this?

I have a Savage F12 in 6.5 x 284 and a couple of hundred SMK 140gn (S1740) bullets. I can't get hold of any SMK 142gn bullets locally. I need to load some 1,000 yd rounds.

 

[NateG]

Yes, there is a reason!

The 140SMK, while potentially very accurate, has a very blunt shape and in a world where there's the 142SMK, 139 Scenar, and several good 140 grain offerings from Berger, there isn't much reason to shoot it. Any of those other 140-class bullets will have much less wind drift. Much less drop, too--which usually isn't a concern for known-distance shooting, but a buddy of mine loaded up a batch of 140SMKs for his 6.5-08 prone gun, swapping out the 142s he ran out of for some 140s. He didn't have enough elevation adjustment range for the 1000 yard line. (He had plenty for the 142)

Basically, don't bother with the 140SMKs. Use any of the "modern" 140-class instead.

 

[mikegaiz]

I shot a 6.5x06 AI for a couple of years at Va.1000 with some success. My light gun shot the 140 SMK best and my heavy gun shot the 142 SMK best. Later I moved to both guns shooting 6.5x284 and the 142 SMK's were the ticket. I agree the 142 have a better shape, but what counts is what your gun shoots best. Some times the dog won't hunt, no matter how hard you try.

 

[jimbo88mm]

Could this be an example of secant vs tangent?
Sierras website doesn't say.

If the 140s are a tangent design then they may be less sensitive to bullet seating.

 

[1066]

Thanks for that guys. I've had a look at the figures now and I can see the 140's have the BC of a turnip compared with some of the others, however, as that is all I've got and no chance of getting anything else at the moment I'm going to load them up and live with the extra 20 odd inches of drop.

 

[birdog]

They are not hard to find. Just have some mailed to you.
At 1,000 you need the high BC.

 

[1066]

They are not hard to find. Just have some mailed to you.
At 1,000 you need the high BC.

Ahh! forgot to mention - I'm in the UK and things are not quite so easy. I went into a local gunshop yesterday to try to order a Micrometer seating stem for a Redding die - "Redding - I've never heard of them"

So, I've ordered 500 SMK 142's and a couple of tubs of H 4831sc but they will take several days to come in (and cost and arm and a leg with one LB of powder now costing well over $60)

It took me eight months of hassel to get a Shilen match barrel for my Savage 6BR.

 

[NateG]

"Ahh! forgot to mention - I'm in the UK and things are not quite so easy."

Well in that case... let me say that the 140SMK is a very accurate bullet, and out of a 6.5-284 you'll end up with pretty similar ballistics to a 6BR shooting a 105-class bullet. And, while the 6br is generally considered "under-powered" for 1000 yard shooting (benchrest, F-class, or high power), it's certainly capable of shooting some very good scores if you stay on top of the wind. (I've shot a 6BRX for a few years for prone long range)

So, until you get your new bullets (or bullet heads, as y'all call 'em? ), you've got a 6br that takes a bit more powder.

 

[1066]

"Ahh! forgot to mention - I'm in the UK and things are not quite so easy."


So, until you get your new bullets (or bullet heads, as y'all call 'em? ), you've got a 6br that takes a bit more powder.

Thanks for that Nate - Thats put things in perspective and made me feel a lot better - I've shot the 6BR at 1000 and not felt too handicapped if the weather is kind.

 

[Laurie]

1066, talk to Norman Clark Gunsmith Limited in Rugby for bullets like the 142 SMK - Norman usually has them in stock. (He's also definitely heard of Redding, being that company's importer.) Norman and his other half plus their retail team will be at Newark on the 25/26th with a stand on the British Shooting & Countryman Show and take literally tons of handloading tools and components to it, most for pre-orders taken over the phone or by email. They also go to many of the big Bisley events like the Imperial and Phoenix that have trade stands attached and customers pick up a year's supply of pre-ordered stuff.

Also consider the Berger 140gn BT Long-Range, another easy to tune tangent ogive bullet. Bergers are imported by Norman Clark and Hannam's Reloading Ltd. The 140 BTLR has a near identical BC to the 142 (0.303 v 0.301 G7 by Bryan Litz) but may or may not suit your barrel better. They are sadly very much more expensive than SMKs in the UK though.

 

[1066]

Thanks for that Laurie - I usually pick up supplies at the Pheonix or Trafalgar from Norman but have found myself short.
I have been shooting the 108 gn Bergers in the 6mmbr and I'm very pleased with the result but when my last couple of hundred are gone I will be l will be looking for a more cost effective alternative - I really can't justify spending over £40 a hundred.

 

[Laurie]

I really can't justify spending over £40 a hundred. [1066]

Yes, I know the feeling! You might get good results with the 6mm Hornady 105gn A-Max. They do really well in some barrels, not the Border on my 6BR unfortunately which has expensive (Berger) tastes.

Brian Fox (Fox Firearms UK) has a shipment of JLKs just arriving around now, so that's another avenue to try. Brian sells Bergers and Viht / Alliant / Hodgdon powders at a very good price too if you can get to Diggle Ranges on a weekend when he has his shop in the range house open.

 

[shoothog]

Im pretty new to this long range stuff. I did not see mentioned the twist rate. Are you all shooting 8" twist? Just curious.
Thanks.

 

[Laurie]

Shoothog,

you're best with 1-8" twist for all 105-108gn long-range 6mm bullets, but 9" provides marginally enough stability under ideal conditions (warm, humid air, low atmospheric pressure). Most people use an eight too in 6.5mm with the 140s, but 1-9" is just OK for most models.