compressed loads

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theflamanguy

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Hi there, I would like to know how dangerous compressed loads are?
I am working up a load for my .308 Win 70 Featherweight using IMR4895 in IVI Cases? Federal 210's. COL of 2.900 to 2.903 using Hornady 150 IB's(I believe the difference is in the plastic tips?)
I started out at 42 gr. and ended at 46 gr. going up in .5 increments.
Paying no attention to the other loads(how full they are), I realized that the 46gr. load came up to the shoulder. After doing some measuring it appears that I have a "slightly" compressed load.
The Hornady manual shows the load going to 46.4gr. as maximum with no reference to a "compressed load"
My question is as stated above, how dangerous can this be?
Thanks.
TFG
 
If the load is listed in a manual and pressure tested, and shows no evidence of pressure problems in your rifle, there is no danger. Many loads are mildly or even heavily compressed, while still being perfectly safe to load and shoot.

So long as you have worked the load up to that level and have not observed any pressure signs, you should be fine.
 
Hornady's data tends to be pretty mild on the high end. As far as compressed loads go, they're actually desireable with real big capacity cases and large diameter bullets in bolt guns - a full case of powder tends to stop bullets from slipping back under big recoil in a magazine. If the data calls for a compressed load, use it - they didn't guess at these loads in manuals and they shoot them all.
 
Compression initself is not bad. On balance, it is better.

But, you are using a military case. less capacity. Load should be reduced about 2 grains in that case. 46 gr of 4895 is probably too much in a militrary case.

A well made rifle does not show pressure very early. You may already be too hot.
 
Compressed loads often give better accuracy because any position sensitivity of the powder is removed. Whether its dangerous or not depends on the powder, the weight of the bullet, seating depth and case volume.

You're using cases with less volume than what the manual lists and IMR4895 is a fairly temperature sensitive powder. You may not see any pressure signs now, but whats going to happen in the peak of the summer? I would either reduce the load by 1.5-2.0 gr. as Ganderite said or use a powder thats less temperature sensitive.
 
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