Hello
Well, I went and did it.. Picked up a S&W M&P 15 Sport II in 5.56 NATO 16” 1-9” twist barrel. I really thought I could live without one but.. Bud’s Gun Shop had a deal I couldn’t pass up. Plus, being a vet I get another 50 dollar rebate. Installed a Lucid HD-7 2- Minute red dot sight on it. This is one sweet shooting rifle.
Naturally I gathered some factory ammo and took it out for a spin and see how it does. I’ll start working with 55gr projectiles first.
What I found locally was some Frontier 55gr FMJ, and American Eagle 55gr FMJ. I had to order the IMI ammo on-line.
The first thing I do with factory ammo is pull at least one down and examine it. If you want to see more details I have it all documented here;
https://postimg.cc/gallery/2c3rect8a/
https://postimg.cc/gallery/1o9ly103e/
https://postimg.cc/gallery/2jdpogbwa/
The bottom line is;
American Eagle had a 27.6gr charge and shot 3044 and 3061 fps
Frontier had a 27.4gr charge and shot 3010 and 3012 fps
IMI had a 27.0gr charge and shot 3018 fps
So… Being the hand loader I am, the first thing that come to mind is, how do I duplicate these?
How ‘bout that, another project..
I stay current on most of the major data sources so went through all the 55gr data and made a reference chart. I do this with a lot of stuff I work with.
So from this I decided on what the work up ladders were going to look like. Just recently finished working with a 7.62 NATO rifle so the powders that I used for that project were appropriate for the 5.56 as well..
Decided on three group ladders working up to, or just shy of the highest listed charge, and watching for pressure signs as it progresses.
Picked up a thousand 55gr FMJ bullets from a major bullet source, and immediately noticed that they were not all the same bullet.. The cannalures were in different places, the ogives were different and weights varied. Great… It appears there are three maybe four different styles in there. My buddies tell me this is quite common with these ‘deals’..
Well I sorted through these and segregated them by cannalure location and size, ogive shape and weight the best I could. So each fifteen rounds representing each powder is loaded with close to the same bullet as possible.
I discovered a coffee can full of once fired LC brass, so that worked out..
Cleaned them up with my Frankford SS pin tumbler. Sized with a Redding SB sizer, trimmed with the World’s Fastest Trimmer, crimped in the cannalures with a LEE Factory Crimp die.
The powders I chose to work with are;
AA2015, AR COMP, AA2230, IMR 8208, AA 2460, H-335, TAC , 748, BL-C(2), W846, AA2520, and CFE223.
All the loads were weighed individually by hand.
Primers used for AA2015, AR COMP and IMR 8208 were Rem 6˝. The rest, CCI 450.
So off the range..
Day one;
The 50 yard target range seemed the best distance to shoot groups with the red dot sight.
Targets are 4” in diameter.
Velocity data taken with an Oehler model 33.
Screens centered 15' from muzzle.
Turns out my Oehler controller has developed an ultra-sensitivity issue. The higher charged loads were reading incorrectly. The targets that say 'No Data' were the ones effected. So after going back and forth with Mr. Oehler, he sent me a brand new controller, never before sold. So last time out I tried it out and it worked flawlessly. Back in business again..
Here is day two;
Shot these loads again after the new controller arrived..
Well, almost every powder managed to shoot some nice groups somewhere along the line.. H-335 and AA 2520 really get with the program with respect to velocity.. The high end loads were warm, but not terrible. The loads in the middle would be a max load in this rifle.
Day 2 target #17;
The Lucid HD-7 sight has a auto-off feature that, in two hours of continuous operation, it will shut itself off. Well I was just squeezing off the last shot, and just when the firing pin was being engaged, the sight went off, so I shot without a red dot. Had this not happened I believe this would have been a excellent group.. Have to re-shoot it sometime.
The factory loads all shoot in excess of 3000 fps and are loaded with 27.0 – 27.6grs of a ball propellant. It would appear that the IMI ammo uses some very similar to AA 2520.
AR COMP; the order got switched. The starting load, 24.0grs, is on the far right of the three targets..
With the exception of H-335 and AA 2520 on the high end, no excessive pressure signs were noted.
I expected a little more out of CFE223..
Here is a graph to see all the velocities from the air..
At the bottom you can see the factory loads velocities and charge weights compared to the hand loads.
So that was interesting.. I hope to do this again with 62gr bullets.. Well see.
Bear in mind this is all relative to one rifle, one shooter, one place and time, one set of components. Change any one variable and this could all change. Don't accept this as loading data. You must do your own work ups with your rifle.
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Originally Posted by RDub
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