7mm-08 SSP velocity vs Rifle?

[dontstrokeme]

Request for 7mm-08 powder selection.

I am going to cut my SPS Varmint in 7-08 from 26" down to 18" and maybe even 16"....I fiqure if a 308Win can run 18" no problem out to 1k then the .284 should make the 7-08 run even better.

Leaning towards the 168SMK, 162Amax, 150SMK, 175SMK.

Looking at Varget ,IMR4064, RL15, RL17

So the sierra book lists the 7-08 in a 26" barrel getting 2600fps from 39.2gr of IMR4064.....then the SSP of 7-08 with 15" barrel lists 2400fps with 38.8gr of IMR4064. For 9" and .4gr of powder I belive that the 15" barrel to loose 200fps is A-ok by me.....so I plan on a 18" barrel.

I am wondering if anybody has played with the IMR4064 with good results in the 7mm-08? Or any other fast powder? Heard that RL17 would be a good powder to try out as well.

Also with that short of a barrel am I wasting my time with the 168gr and above? If the 150gr would make more in velocity to compensate for the lower BC?

I have researched the 7mm-08 to run in a short barrel for the last 1 1/2 and now have it on order and want to gather a selection of powders and bullet weights.

If anybody has projections from Quickload or real world short barrel 7mm-08 results I am trying to find a powder that can get full burn in 18"....could always just start throwing pistol powders in 50/50 with RL22!!!!

Any help is great.

 

[Topstrap]

Re: 7mm-08 SSP velocity vs Rifle?

I shoot 44gr IMR4064 with a 140VLD Berger in my 14" XP-100 pistol and have no prob getting to 1000. I'm getting about 2650 to 2700fps depending on temperature with that load and bullet. I've tried Vargent and IMR 4350 and they did group well but had less velocity. I did use 150gr Sierra BT Match and they also shot very well out to the 900 yard target last year but the Berger carries about 50" higher so I went with them for this years competition load.

With my short barrel and limited velocity I've found the 140gr and 150gr bullets work very well and have found no need to try a heavier bullet at a slower velocity to keep up with the rifle guys shooting heavier bullets.

If I could get more velocity I'd try the heavier bullets but there is a tradeoff based on barrel length and bullet weight and you need to find what works best with what you have to work with.

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[dontstrokeme]

Re: 7mm-08 SSP velocity vs Rifle?

So you seem to be getting a complete burn of the IMR4064 in the 14" barrel? I am guessing...the Sierra book shows a lower max charge for 140gr and 15" barrel but if you went higher than max listed I would assume it benefited you.

Also was that 50" for the Berger actual or calculated?

 

[Topstrap]

Re: 7mm-08 SSP velocity vs Rifle?

Calculated using JBM. I was using 140 Sierra SPBT starting last year and switched to the 150 Sierra HPBT Match and gained nearly the same amount that was expected at 900 yards which was what JBM also showed so I'm assuming that the Berger showing the 50" gain can also be expected. It has a lot higher BC. Soon as weather breaks we're planning on hitting the 900 yard range to test the Bergers and also the calculated settings on the new adjustable mount.

Berger recommended putting the bullet into the lands and as I experimented with it I did get a couple loads with the 4064 that hit 2745 but they did not group as well at 100 but when I got to .015 off lands they shot their best and had a decent velocity. Will play more with it when weather warms up and can try more experiments at the range shooting actual distances.

When I went above 44gr of 4064 I didn't gain any velocity so that seems to be max in my gun for velocity gains at a safe level. I don't have a brake on the barrel and it is the factory barrel that came on it from the Remington Custom shop with a taper down to about 5/8" at muzzle. It does jump a bit but we're used to that and it doesn't have an excessive muzzle blast any different than what the rifles have. On a decent day if I do my part it'll do 1/2" to 1" groups at a 100 with a bipod and my wooden wedges under the grip. Not benchrest groups but plenty good for hitting the 12" and 15" plates at our matches.

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[dontstrokeme]

Re: 7mm-08 SSP velocity vs Rifle?

Thanks for the help.

 

[dontstrokeme]

Re: 7mm-08 SSP velocity vs Rifle?

BTT

I am loading for the 18" now and only have Magnum CCI primers....I am starting low and working 1gr increments. Is there a general rule of thumb for using Magnum primers in place of Standard?

Also if anybody has info for max loads of Varget or IMR 4064 with 162gr AMAX's that would be great!!