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Aaron B

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A question for 7mm WSM shooters
Jun 18^th, 2012 at 2:30am

I'm having my 25" 7mm WSM barrel put on a T3 and wondering if I can get away without altering the magazine length (short).

I tested some powders I have on hand with the 162gn amax seated to just under mag length

63gn RL17 (powder can be heard rattling around in the case)
65gn n560 (rattles around still, but less than above)

What are people achieving with loads less than say 65gn? Loads/chronied velocities/bbl length.

Will this be a limitation?

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smiddy Forum Font Offline hunting, not working Posts: 1280 Chch/westport - up the hill Gender:	Re: A question for 7mm WSM shooters Reply #1 - Jun 18^th, 2012 at 5:58am Are you after velocity? If you are then it doesn't cost much to alter bolt stop and put a long mag in, then you can get the throat bumped forward aswell
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Aaron B Donor Member Offline Posts: 737 Napier Gender:	Re: A question for 7mm WSM shooters Reply #2 - Jun 18^th, 2012 at 8:53am The bolt stop is easy but it's the mag that's trickier. I've tried the Tikka T3 LA mag from my 6.5x55 and it's too narrow. So im stuck with the fatter "SM" marked mag short magazine, at least as far as I know
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stug Forum Senior Online I Love The FishNhunt Forum Posts: 502 Oxford Gender:	Re: A question for 7mm WSM shooters Reply #3 - Jun 18^th, 2012 at 8:55am What about a magazine for a 7mm mag or a 300 win mag?
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Aaron B Donor Member Offline Posts: 737 Napier Gender:	Re: A question for 7mm WSM shooters Reply #4 - Jun 18^th, 2012 at 9:00am I'm going to double check but they're all the same part number as listed by Tikka
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stug Forum Senior Online I Love The FishNhunt Forum Posts: 502 Oxford Gender:	Re: A question for 7mm WSM shooters Reply #5 - Jun 18^th, 2012 at 9:24am Otherwise the dremel is your friend From the couple of times I have looked at T3 mag the blocker at the back seems to be hollow. Grind it out and if necessary put some epoxy (Devcon or similar) in the back to fill it to the right depth and then reshape the feed lips in the rear section.
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7mm Magic Active Member Offline I Love The FishNhunt Forum Posts: 468 Taranaki Gender:	Re: A question for 7mm WSM shooters Reply #6 - Jun 18^th, 2012 at 9:45am Why do you want to load it so light?
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Aaron B Donor Member Offline Posts: 737 Napier Gender:	Re: A question for 7mm WSM shooters Reply #7 - Jun 18^th, 2012 at 10:40am To get away with the standard magazine. I was wondering what velocities people were getting with the faster powders. I've managed to pop the base off the mag and in the process of dremelling it now. Will post a photo once it's done, just got to shape the feed lips now.
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7mm Magic Active Member Offline I Love The FishNhunt Forum Posts: 468 Taranaki Gender:	Re: A question for 7mm WSM shooters Reply #8 - Jun 18^th, 2012 at 12:16pm 69gn N560 will give you about 3000+fps.
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FlinchedAgain Forum Senior Offline I Love The FishNhunt Forum Posts: 873 HB Gender:	Re: A question for 7mm WSM shooters Reply #9 - Jun 18^th, 2012 at 4:07pm You have 2 options, get a 7mm rem mag magazine and open up the feed rails a bit, or get a 300wsm mag and mill a bit out of the back of the magazine. It will be cheaper also to modify the bolt stop yourself than it will be to replace it.
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FlinchedAgain Forum Senior Offline I Love The FishNhunt Forum Posts: 873 HB Gender:	Re: A question for 7mm WSM shooters Reply #10 - Jun 18^th, 2012 at 4:10pm or you could just put more powder in and see how she goes.
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DazzH Active Member Offline I Love The FishNhunt Forum Posts: 191 Tauranga Gender:	Re: A question for 7mm WSM shooters Reply #11 - Jun 18^th, 2012 at 6:36pm 63.8 gr RL17 162 A max gives me about 3180 from a 24" barrel. Mine are seated to an OAL of 3". If you're seated at 2.8ish it might pay to back it off a little for a starting load.
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Aaron B

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Re: A question for 7mm WSM shooters
Reply #12 - Jun 18^th, 2012 at 7:25pm

Pretty easy to lengthen the magazine. The hard part is popping the bottom off its clips.

Then used a rotary bur tool to remove all the hollow plastic.

Use a pointy one to shape the extension of the feed rails.

Finally just soothed up the inside with wet and dry and reassemble.

Feeds well and took maybe 45mins start to finish. Gonna glue in a piece of plastic behind the riser piece to space it nicely but it's not really necessary.

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stug Forum Senior Online I Love The FishNhunt Forum Posts: 502 Oxford Gender:	Re: A question for 7mm WSM shooters Reply #13 - Jun 19^th, 2012 at 8:17am Awesome job! I am sure that there will be a lot of T3 owners getting out the dremel now. Do you need to shorten the bolt stop as well?
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Aaron B Donor Member Offline Posts: 737 Napier Gender:	Re: A question for 7mm WSM shooters Reply #14 - Jun 19^th, 2012 at 9:48am The bolt stop is longer than the standard SM mag length but I guess it depends on your OAL. I still had to increase my bolt throw a couple mm. I have the older solid steel bolt stop which is easy to grind (two mins with a file), unlike the newer hollow one which would be a little trickier but still no big deal
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BD Active Member Offline I Love The FishNhunt Forum Posts: 132 Gender:	Re: A question for 7mm WSM shooters Reply #15 - Jun 29^th, 2012 at 5:40pm does it feed with the bullet follower being shorter? does the rim get caught on the bullet follower being shorter? I was thinking of doing the same thing so keen to see how it works.
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MW28NZ

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Re: A question for 7mm WSM shooters
Reply #16 - Jun 29^th, 2012 at 6:26pm

BD wrote on Jun 29^th, 2012 at 5:40pm:

does it feed with the bullet follower being shorter? does the rim get caught on the bullet follower being shorter? I was thinking of doing the same thing so keen to see how it works.

I modified the mag on my t3 wsm and it feeds perfectly. I cut the stop out of the mag and put a long action mag base and bullet follower into the magazine and put a long action bolt stop.

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BD Active Member Offline I Love The FishNhunt Forum Posts: 132 Gender:	Re: A question for 7mm WSM shooters Reply #17 - Jun 30^th, 2012 at 10:25am good to know.
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