Range Report 240 SMK and 1 in 10" twist barrel

[head2h2o]

Review of the Sierra manual suggests that the 240 SMK requires a 1 in 9" twist to stablize. A call to the guys at Sierra confirmed this. I figured, what the heck, let me see if a Sendero chambered in 300 RUM with the standard 1 in 10" twist will stablize it. Sure enough, it did.

My groupings with Retumbo measured as follows:

All percentges are from the max load of 86.5 gr.

95 and 97% were sub 1/2 MOA
98% - sub MOA
99% was .627
100% was .647

Not the best in the world, but good numbers I felt for a bone stock Rem 700 Sendero using Nosler brass.

Just wanted to pass this along in case anyone else wanted to shoot the heavier stuff but had questioned their twist rate.

Velocity on the 100% load averaged 2729 and there were no signs of pressure and reasonable case capacity left after seating the bullet .010 off the lands.

 

[9H_Cracka]

Re: 240 SMK and 1 in 10" twist barrel

Not surprised with a RUM load of powder behind it.

More MV = more RPM of the bullet in a given twist rate.

Thanks for the intel - now we need Montana Marine to test them out of a 20" 10 twist 308.

 

[head2h2o]

Re: 240 SMK and 1 in 10" twist barrel

That would be interesting for sure. I would love to see the ballistics on that. Maybe someone will be a forerunner and try it.

 

[MontanaMarine]

Re: 240 SMK and 1 in 10" twist barrel

I did test the 240s in my 1/10 30-06. At 2610 fps via RL22 they were very accurate at 100 yards:

http://smg.photobucket.com/albums/v461/m...nt=Img_5163.jpg

I did some rock shooting past 1000 yards and they seemed very accurate and consistent.

I'd try some in my 308, but it's a 1/12 twist so I think it would be a futile waste of bullets.

I did recently shoot some 220 SMKs through the 1/12 twist 308. At 2550 fps via RL17 they were accurate and stable. I went all the way out to a mile on rocks. 94 moa, they were consistent, and would have passed through to subsonic.

All this was done at 4500' elevation.

 

[MontanaMarine]

Re: 240 SMK and 1 in 10" twist barrel

Over at Accurate Reloading, Saeed has some interesting results posted, shooting the 240 SMK from a 1/10 twist 7.62x39mm. It was plenty accurate at MV's around 1800 fps.

http://www.accuratereloading.com/76239.html

 

[head2h2o]

Re: 240 SMK and 1 in 10" twist barrel

I may have to just try that with the 220 SMK and the 308. I have a 30-06 with a 1 in 10 twist rate, but it is a hunting rifle. It weights in at a whooping 6-7 lbs and already packs a punch with 165gr bullets. Cannot imagine shooting it with 240 gr. What the heck, I may load it up for kicks and grins anyway.

 

[aggiesig]

Re: 240 SMK and 1 in 10" twist barrel

found this post on the google search so sorry if it is rehashing dead topics...

Has anyone tried to shoot the 240 gr. subsonic out of a 1-10"???

I am thinking about picking of a savage 10fp or a stevens 200 and threading it for my AAC to see if this works but those guns are 1-10" from the factory.

 

[MontanaMarine]

Re: 240 SMK and 1 in 10" twist barrel

1/8 is the norm for subsonic 240s.

 

[mdesign]

Re: 240 SMK and 1 in 10" twist barrel

Interesting...been wanting to work with the heavies. My barrel is 1/11.25, I'll have to see how it goes.

 

[coldbeerchief]

Re: 240 SMK and 1 in 10" twist barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: aggiesig</div><div class="ubbcode-body">found this post on the google search so sorry if it is rehashing dead topics...

Has anyone tried to shoot the 240 gr. subsonic out of a 1-10"???

I am thinking about picking of a savage 10fp or a stevens 200 and threading it for my AAC to see if this works but those guns are 1-10" from the factory. </div></div>

1:10 will NOT stabilize subsonic 240 SMKs.

or 220 SMK, or 208 A-Max, for that matter.

 

[shoot4fun]

Re: 240 SMK and 1 in 10" twist barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Insert Name Here</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: aggiesig</div><div class="ubbcode-body">found this post on the google search so sorry if it is rehashing dead topics...

Has anyone tried to shoot the 240 gr. subsonic out of a 1-10"???

I am thinking about picking of a savage 10fp or a stevens 200 and threading it for my AAC to see if this works but those guns are 1-10" from the factory. </div></div>

1:10 will NOT stabilize subsonic 240 SMKs.

or 220 SMK, or 208 A-Max, for that matter. </div></div>

Tell us about your actual experiences and why you emphatically state the above. We'd all love to hear more.

 

[aggiesig]

Re: 240 SMK and 1 in 10" twist barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Insert Name Here</div><div class="ubbcode-body">
1:10 will NOT stabilize subsonic 240 SMKs.

or 220 SMK, or 208 A-Max, for that matter. </div></div>

Sounds like you have already gone where I am trying to go. Have you tried out the Lapua 200 gr. subsonic bullets?

http://www.midwayusa.com/viewProduct/?productNumber=381996