7mm Twist

[Elwood]

Has anyone had any experience of using a 1-10 twist 7mm barrel for shooting 162 grain to 168 grain projectiles? or does the 1-9 twist work?

 

Berger recommend a 1-10 twist for their 168 gr VLD's and JLK state 1-9.5 twist for the 168 gr JLK.

 

I emailed all the major barrel manufactures and asked their opinion, only three replied, Bartlien, Brux and Krieger, they all said 1-9 twist as it will also shoot the 180 grain projectiles.

 

This my plan for F class open world domination! which is to use the 168 gr JLK in a 284 Shehane. Using N560 I should be able to hit 3100 fps and hopefully still have barrel life.

 

I know the 168 JLK has a inflated BC of .690, even if you bring this down to .660 which is the same as the Berger 180 VLD it will still equal the ballistics of the 7 WSM's.

 

There has to be a flaw in my plan, why hasn't it been done before?

[6mmBR]

There has to be a flaw in my plan, why hasn't it been done before?

Perhaps no one has tried yet

I would have thought at those speeds a 10 twist shouldn't be a problem. Twist rate may become more of a factor in lower power cartridges like the 7-08.

I've just ordered some of the new 162 Hornady BTHPM to give a whirl these hopefully have an honest B.C of .610 so pointing them should increase B.C a little.These should be able to go a bit faster again over a 168? Hope to make a super fast short range load. I will try them in my old barrel with some Rel 17 and H4831SC or maybe N550?

Good luck in your quest and I'll let you know when we find that 10 twist barrel

Cheers

Dave

[6mmBR]

ps

Do JLK's have dimples ?

[dannyt]

Ive tryed 162 A Max and 168 bergers in 9 twist barrels in 7/300 wsm and 7 shehane and both seem to work well , I think I was useing RL 17 good ES and SD, Only shot them to test out to 300 yrds but they look ok . be a good short range round in the shehane . I could get 3150 with out much trouble in the 7/300 and 3050 in the shehane .

I will resume more testing now my work load is easing up a bit,(Let use know how you get on )

[taylor]

with the lighter bullet and 560 i dont think your barrel will last longer as your putting more powder down the same hole and 560 eats barrels up like no other ,i would go 1-9 twist at least if it doesnt work throat it out and shoot the 180 grn

speak with hugh ingles he tryed the 168 berger in the shehane for the exact same reason and i tryed the 162 a-max and when you go above 3k the vertical opens up ,i think the 180 is the way to go heavy bullet going slower rather than light going fast especialy at long range ,in my eyes the tighter the vertical at long range the better

[Elwood]

with the lighter bullet and 560 i don't think your barrel will last longer as your putting more powder down the same hole and 560 eats barrels up like no other ,i would go 1-9 twist at least if it doesn't work throat it out and shoot the 180 grn

speak with hugh ingles he tryed the 168 berger in the shehane for the exact same reason and i tryed the 162 a-max and when you go above 3k the vertical opens up ,i think the 180 is the way to go heavy bullet going slower rather than light going fast especially at long range ,in my eyes the tighter the vertical at long range the better

 

Hi Grant, good suggestion about using the 1-9 twist.

 

I did speak to Hugh about it and he said he never really got the accuracy with them and so didn't pursue it. I know he had a 1-9 twist and just wondered if it might have been a twist rate problem.

 

Do you have any theories as to why the elevation goes after 3000 fps? I certainly agree with you about elevation being the killer at long range, there's nothing worse than calling the wind right only to score a high or low 4!

 

Berger themselves recommend a 1-10 twist but as Dave says that's probably more suited to shorter hunting bullets, JLK recommend 1-9.5 twist.

 

I have 100 JLK's here and will see what I can do with them, I have RL17, N560 and H4831SC so it should be interesting.

 

No dimples Dave!!

[taylor]

no - no idea why it maby the twist , but their is is a node at about 2900-2975 in 4 different barrels in 1-9 to 1-8 twists but didnt try in a 1-10 you never know it could work well for you i found the tighter the twist the lower the node so it might be rpms ,maby if you realy push it you might find another node ,but i dont recomend it ,i have pushed it right up till i got about 2-3 reloads out of a case and it didnt work for me ,

i think its the same with the 7 wsm you can get killer vertical if you dont push it to hard

[taylor]

i think it will be hard to beat a 180 berger in a 7 wsm pushed at nearly 3100 -3200 fps

[6mmBR]

i think it will be hard to beat a 180 berger in a 7 wsm pushed at nearly 3100 -3200 fps

Hi Grant what powder are you using in the WSM, toying with the idea of going over to the dark side and a 7-270WSM.

Going to give the Shehane a try at Diggle got 2930 fps with 58gns of H4831SC with a 180 Berger VLD and an ES of 10 fps.

Will take the old gun in case as it was very difficult to test for accuracy with gale force winds.

Cheers

Dave

[1967spud]

I just had a thought.

 

Has anyone acklyised the 7mm WSM yet ?

 

no but i am thinking about a 7-o8 baer improved for my next shrot range f class gun

[6mmBR]

I just had a thought.

 

Has anyone acklyised the 7mm WSM yet ?

I don't think there would be any point as the case already has a 35 degree shoulder against the Acklies 40 degrees.

Also the case already has excess case capacity to what is require. Hence why people opt for the .300/.270 WSM as a parent case as they have slightly reduced capacity(and Norma brass) and a longer neck.

Cheers

Dave

[dannyt]

Les Bacon has had a flirt with the 7mm338 and gets an easy 3400 ftps ,if i remember before the bullets blow up nicely around 500yrds , i bet he would sell the reamer for about 5 bob and pay the post for you .

 

PS this is not a dig at Les , he built the 7/338 to shoot his new hand made 210grn 7mm bullets ,the bearing surface was to great and ripped the jackets up bit off topic sorry

[taylor]

58 grns is one of my old loads in the shehane it will work trust me

i am using R25 and at the min its showing great promise verry accurate at 400yds groups way under the inch and getting 3100 with es 11 and sd 4 ,but havent tryed at 1k yet but will at diggle ,just got stock back today from painters ,but up to now its as accuarate as my shehanes but with mental speed

go for it dave

[dannyt]

58 grns is one of my old loads in the shehane it will work trust me

i am using R25 and at the min its showing great promise verry accurate at 400yds groups way under the inch and getting 3100 with es 11 and sd 4 ,but havent tryed at 1k yet but will at diggle ,just got stock back today from painters ,but up to now its as accuarate as my shehanes but with mental speed

go for it dave

 

 

Grant are you shoot a wsm well i never , Wash your mouth out with soap.

[taylor]

sick of getting beat by all you boys shooting canons so i thought i would join you on the dark side lol

[dannyt]

Grant you dont get beaten that often mate , the old shehane has life in it yet.

[taylor]

thanks danny but i aint givng up on it ,just a new project i plan to run both all next year shehane for 8 and 900 and wsm for a 1000 back need to know whats best to take to raton if i get picked this time

[dannyt]

I think thats a smart call Grant ,Do you know of any good throat erosion data on the wsm with the cooler powders, the barrel life seems to be extending now that people are starting to shoot the magnums a tad slower

[taylor]

not realy i have shot 150rounds and mine aint moved at all ,i know of a few others that aint moved much either ,vit 560 seems to melt the throats out fast

i think if we string shoot next year i am defo shooting the shehane .as i dont think the wsm will last more than 600 rounds and will heat up somthing bad with a string of 20+2

[dannyt]

I know you are a big believer in recrowning if i remember right have you seen any difference in the wsm needing more or less attention

than the shehane

[taylor]

to early to say yet danny ask me after diggle lol but i think it will wash out much quicker for sure takes 10 more grains of powder over the shehane

[6mmBR]

58 grns is one of my old loads in the shehane it will work trust me

i am using R25 and at the min its showing great promise verry accurate at 400yds groups way under the inch and getting 3100 with es 11 and sd 4 ,but havent tryed at 1k yet but will at diggle ,just got stock back today from painters ,but up to now its as accuarate as my shehanes but with mental speed

go for it dave

Thanks Grant looks like you and I both will be stepping into the unknown at Diggle with our rifles.

Cheers

Dave

[6mmBR]

sick of getting beat by all you boys shooting canons so i thought i would join you on the dark side lol

My thoughts as well, lucky have a nice 1.250" straight through Bartlein 9 twist for the job.

See you guys at Diggle.

 

ps Danny mate are you booked in the sunfield and what time are you arriving?

Cheers

Dave

[dannyt]

yes Dave iam in the suning diggle job. iam easy on arrival do you want to go for a bar meal friday or will you be to late ?

[1967spud]

My thoughts as well, lucky have a nice 1.250" straight through Bartlein 9 twist for the job.

See you guys at Diggle.

 

ps Danny mate are you booked in the sunfield and what time are you arriving?

Cheers

Dave

 

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