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Old February 9, 2013, 04:18 PM   #17
Unclenick
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Join Date: March 4, 2005
Location: Ohio
Posts: 21,022
To confirm, Hornady's manual says 35.8 grains minimum to 42.3 grains maximum of N135 under the 155 grain A-max seated to 2.800" COL in a Hornady Frontier case with Winchester WLR primer. This is to go from 2200 fps to 2700 fps. That low end is pretty low.

I generally like N135. It's my favorite 150 grain bullet powder in .30-06 for the Garand because it's bulk density is low enough that it fills the case better than many powders, yet is still fast burning enough to produce low gas port pressure relative to the velocity it achieves, and these are reasonable but not high for that gun.

You'll have to tell us what other components you are using. What your rifling twist is, your barrel length, etc.

As has already been stated, the low point of impact (POI) is due to the muzzle having deflected upward at the start of recoil, then begun to swing down again by the time the bullet exits. This imparts a downward drift to the bullet, causing low POI. You need to get the bullet out of the muzzle faster.

Don't worry too extremely about exact maximum pressures. You have to know the way the pressure standards work is based on a standard deviation of 4%. That's pretty big. Most handloaders pretty easily do better. Figure that for your N135 loads to be out that far out, only 19 in 20 would have to have their powder charges within a grain of your nominal charge weight. 5% could be more than a grains from your nominal charge weight. I don't know any powder measure that would throw N135 that badly. A high speed powder dispensing system like manufacturers use, yes. But not one running at the speeds a human arm can go up and down and with a pause while the next case lines up.

Since you are still learning to shoot, I suggest you try Dan Newberry's OCW system as a starting point for your load development. If you get really good, there are refinements Mr. Newberry eschews, but at your current level of shooting you won't benefit from benchrest loading techniques. The first thing is to get you on paper. As suggested, you want the same POI from your rounds, then to adjust your sights. If the commercial match shot well for you, then it is likely other loads that work well will not be far from that same POI with the same weight bullet.

For some suggestions about how to shoot better in general, you may find this article interesting.
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