Magnum primers in a 260rem/6.5cm

Caveman0101

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Joined
Mar 3, 2008
Messages
179
Location
Colorado
Running out of Fed 210s but got my hands on 215s. What adjustments do I need to make to my loads when I change to the magnum primers?
 

MagnumManiac

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Joined
Feb 25, 2008
Messages
3,150
I use mag primers in many standard cartridges, 222, 22-250AI, 6.5-284, 25-06, 338-06 & 45-70.
I work up from 5% below max with ALL primer types, if the mag primer shows the tightest group, I run with it.

If I were to change to a mag primer in a proven load, I would re-work the test from scratch, there is no hard & fast rule that a reduction in charge weight and working back up to the old velocity will result in the same velocity node.

Cheers.
:)
 

codyadams

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Joined
Jan 7, 2015
Messages
3,495
Location
Southwest Wyoming
Going from BR-2 and BR-4 primers to magnum primers in my .260 AI, I noticed about 40 fps average increase, as well as my e.s. goes from single digits, s.d. around 4 or 5 fps, up to 20-30 fps e.s., and s.d. in the teens or more. I don't use mag primers in standard cartridges because this has been my general experience. YMMV.
 

scottishkat

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Joined
Jul 19, 2014
Messages
596
I have found over time that best accuracy with the 260 rem has been with Rem 9.5 primers. I've got literally hundreds of targets shot with 3 different primers 210M, BR2 and 9.5's the vast majority are moa or better. The most targets that have accuracy in the .5 moa or less range are with 9.5,s.

I have never tried 215's or magnum primers in the 260 rem but I have read to many stories about the use of magnum primers with ball powders in 7mm08 to discount the possibility that excellent could not result. I would not load up a bunch until proven twice or more.

It depends on how stiff your powder charge is but I would drop back at least 1 grain and please post your results.

Good luck and shoot straight
 

bigedp51

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Joined
Dec 10, 2010
Messages
1,022
Food for thought, Remington ran Lake City from 1941 till 1985 and used their primers for all small arms ammunition. And they had to work with harder to ignite Winchester double base ball powders.
Now look at the photos in the link below and the baby flame thrower Remington 7 1/2 and 9 1/2 primers.

Primer Flash Test Photos
http://www.6mmbr.com/primerpix.html
 

KMG

Well-Known Member
Joined
Feb 11, 2012
Messages
183
Location
HINCKLEY, IL
I have found over time that best accuracy with the 260 rem has been with Rem 9.5 primers. I've got literally hundreds of targets shot with 3 different primers 210M, BR2 and 9.5's the vast majority are moa or better. The most targets that have accuracy in the .5 moa or less range are with 9.5,s.

I have never tried 215's or magnum primers in the 260 rem but I have read to many stories about the use of magnum primers with ball powders in 7mm08 to discount the possibility that excellent could not result. I would not load up a bunch until proven twice or more.

It depends on how stiff your powder charge is but I would drop back at least 1 grain and please post your results.

Good luck and shoot straight

I have found the same thing in my standard 260 Rem. 9.5's have best accuracy & sd's.
 

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