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How many groove barrel for 7mm wsm

 
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  #1  
Old 03-20-2013, 09:14 PM
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How many groove barrel for 7mm wsm

How many groove barrel should I get for a 7mm wsm and why? I'm planning on shooting 160gr accubonds to 168 gr berger vlds out of a 26" #3 barrel with a 9 twist.
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  #2  
Old 03-21-2013, 05:42 PM
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Re: How many groove barrel for 7mm wsm

4, 5 and 6 grooved 28 caliber barrels have all won matches and set records. Pick one.
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  #3  
Old 03-21-2013, 05:47 PM
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Re: How many groove barrel for 7mm wsm

I like the 6 grove Harts or the 5 C Broughtons for a 7mm. Anytime I plan to use an high expansion bullet, best suited for long range hunting, I like more groves with less jacket scribing going on. I feel this will let the bullet hold together better when taking game at closer distances and also why I only use enough twist rate to effectively stabilize the bullet of choice. With all the 7's I have put together the Harts and Broughts have been very accurate to very long distances.

Jeff
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Old 03-21-2013, 06:59 PM
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Re: How many groove barrel for 7mm wsm

I am debating the merits of 3 groove vs. 5 groove. I'm hoping someone here can discuss the reasons for the differing number and how to choose which is right for for my application. I know guys win with all differing groove paterns and I could go with what I know will work but I keep hearing threads mention higher velocity with some 3 groove. So why not 3 groove vs 5R and is it common to pick up a few fps ?
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Old 03-21-2013, 09:42 PM
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Re: How many groove barrel for 7mm wsm

The only real test of groove count is to first determine what the bore and groove diameters will be.

Second, what will be the width and shape of the groove that also forms the lands as well as the cross sectional area. of the hole in the barrel.

Third, agree on the ammo to be used and peak pressure level to be used for testing velocity.

If any comparison's not made to these standards, the velocity numbers will be bogus.

The reason 4 grooves have been the standard for decades in 30 caliber military barrels is their depth, shape and width require minimal engraving of the bullet and weakening of its jacket as well as long barrel life and good accuracy along with easy, efficient manufacturing tooling. Other types start changing things.

When Sierra's 30 caliber 155-gr. Palma bullet was introduced, several folks tried 5- and 6- groove barrels that shot heavier ones very accurate. Neither shot them as accurate as 4-groove barrels.
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Old 03-21-2013, 09:51 PM
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Re: How many groove barrel for 7mm wsm

Quote:
Originally Posted by Bart B View Post
When Sierra's 30 caliber 155-gr. Palma bullet was introduced, several folks tried 5- and 6- groove barrels that shot heavier ones very accurate. Neither shot them as accurate as 4-groove barrels.
Bart, to clarify, "them" being the light 155 gr 30 cal bullets correct?

This was not the case with the heavy for caliber bullets? correct?

Thanks
Jeff
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  #7  
Old 03-22-2013, 05:17 AM
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Re: How many groove barrel for 7mm wsm

Quote:
Originally Posted by Broz View Post
Bart, to clarify, "them" being the light 155 gr 30 cal bullets correct?

This was not the case with the heavy for caliber bullets? correct?

Thanks
Jeff
Yes.
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