Barely over half full 7 mag loads

W

Wendyj

New member
Been using IMR 4831 from 61-63 grains. Ran out and noticed Nosler listed the IMR 4064 at 49 gr starting point on up. Loaded up 10 at 51 gr which is about mid load. What it likes in 4831 anyway. Brass is only tad above half full case of powder. I'm a little Leary of these. Anyone ever use loads that were way below the bottleneck. Seems like a lot of empty space to build up pressure. Manual shows same oal as 3.290. For 165-168 gr with this load. If this isn't safe I'd rather pull them. Shows speed around 2450 fps. Loading 308 and 7 mag I am either close to powder or right on it. The 4064 I bought for 178 gr Amax in 308 but Nosler shows load data as stated for 7 mag. What do you think. Shoot or pull.
 
I'm confused with what you are asking so, I just looked at the IMR site and saw these loads listed.

.308 168 grain Sierria bullets. 41.5 grains to start. 45.9(C) is the max. 2.80 COL. Federal 210M primer. Winchester brass. Trim length 2.005"

7mm 130 grain Speer bullets. 52.0 min-55.4 max. 3.185" COL. Winchester brass and LR for the primer. Trim length 2.490"

As far as the case being under filled in the 7mm, it appears the pressure is fine. Looks like the makings for a good load for the 308. I wouldn't pull them according to this data. I know the bullets are different but, that is just me. It isn't like you are teetering on the edge according to their web page shooting similar BT bullets. God Bless
 
Well, 4064 is certainly not a popular powder for the 7 Rem mag. A recent Speer manual does not show any loads, regardless of bullet weight, and Lyman 49th only shows one load with 4064 and this is with a light 140 gr bullet and around 46 to 54 gr of the 4064. The slower powders like 4350 and 4831 with heavier bullets like you are using (168 gr I think you said) are the way to go. But considerable air space left in a case is not all that uncommon. For example, 45 to 48 gr 4895 or 4064 for .30-06 M-1 Garand loads are standard through a variety of bullet weights and considerable air space remains in the case which is not a dangerous situation. Your 10 rounds will be safe to shoot but you may not want to continue with that loading so salvage the 10 bullets if you prefer to.
 
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I hadn't tried the 4064 on anything but heavy bullets in the 308. Nosler load data site is same as their manual. I was out of IMR 4831 which is what I load the magnum with. I was looking for an alternate powder to buy if I couldn't find the 4831 which is quite possible seems like lately. I noticed at the top of the page the IMR 4064. I just wasn't sure about cases filled so low. Not what I want and if I find powder today I will pull them.
 
Wendy,

For the 7mm mag, look for something even slower such as IMR7828 or RL22, or RL23. Remington has used 7828 in factory loads for years and RL22 works great. The 4350s and 4831s will work, but are still a bit fast. 4064 is even faster, but is fine for the .308.
 
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