Monday, September 20, 2010

Range Report

Despite the multitude of things that come up on my weekends, I got to do some shooting in preparation for the hunting season that I most certainly will not get to partake in.

Saturday was the best day. I ended up at my sister's house to test fire the 308 to make sure that I had properly re-assembled the gun. I picked up another 4' plastic folding table from Home Despot, as they are actually stable enough to shoot off of. With a Caldwell shooting bag up front, and several Brownells shooting bags under the deadly pistol grip and buttstock, I had the most stable shooting rest that I've had in years. The range was 119 yards from the muzzle.

I achieved what I was looking for, in that I have determined that 168 grain Federal Gold Medal Match are not the bee's knees for my gun, and that my earlier handloads of 165 grain Sierra Game Kings on top of 43.4 grains of Reloader 15 are good shooters, but a little slow for my tastes. All I was asking for was some consistency, and I got that. As usual, time ran out and I had to pack it up.

Time is my mortal enemy; when I die I'm going to track down Father Time and kick his punk ass for leaving me perpetually short all these years. The bastard.

Here's the work that I got done:



The shot in the center of the paper was to see where I was at after taking the gun apart two weeks ago. Two inches low is not bad considering I had removed the scope and barrel entirely, and then put it all back together again. Gotta love ARs! With a quick scope adjustment, the next three rounds went into the top center target, which verifies why you should never take a three shot group as the absolute truth. That little bughole group looks great and all, until you see the two five round groups bracketing it on the left and right at the top. Those are the 168g FGMM. I think I pulled the extreme right shot on the right target; this ammo shoots better than that.

The lower five shot group on the right were my handloads, and I wasn't at all impressed with it, so I decided to shoot a ten shot group, which is on the left. The one shot furthest to the left was my fault, as I was riding the sear and let that shot go before I had paused my breathing. All in all, even taking in the pulled shot, the group measured 1.7" which is a little outside of MOA. Ten shot groups tell a better tale.

Sunday was not a good day at the range. Father Time had me on a shorter string, and the worst of it was that I had not eaten the first thing all day, and during my afternoon session my hands were shaking so bad I doubt I could have fed myself with a fork. My groups reflected this:



Crappy cell phone pick tells the tale; five shot group in lower right target (not the three targets at the bottom that you can only see half of) are FGMM, consistently inconsistent, which is what I wanted to know. All of those random shot holes along the bottom are my wheel-weight cast, handloaded 102 grain LRN .380 acp fired from 15 yards off hand. I have not yet pulled the velocity data off my chronograph from those because of the aforementioned problem with that prick Father Time, but they didn't blow the gun up, and they all hit pointy side first. All is well with those for right now, and I'll have more information on them soon I hope.

What is astounding to me is the five shot group in the center, and the eight shot group at the top left. Those are 150 grain factory Remington Cor-Lokt that I keep buying because they're cheap, and I use them to foul the bore before shooting expensive match ammo or carefully loaded hand loads. They have astonished me before. During the top left group, my hands were shaking terribly, which is why they are strung out horizontally -- and they were fired last, hastily as I was out of time, and while the barrel was already too hot to touch from firing the FGMM . The vertical dispersion is telling, as is that five shot group. I went ahead and dialed the scope in on those; time to buy a few more boxes of em'.

Guns have personalities like people, and it makes sense that this rifle would tell me that it likes something in particular. Those Remingtons are crimped along a cannelure, which I strongly believe is why they are so consistent in this auto-loading rifle. The feeding cycle is way more violent in an AR than with a bolt gun, and in non-crimped ammo like the FGMM, I have found that the bullet jumps forward from the inertia of feeding, which makes it inconsistent. Also, I have gotten more consistent accuracy in the past from flat based bullets like the Cor-Lokt over boat tailed bullets. Too bad the B.C. on flat based bullets suck; I won't be shooting 1,000 yard matches with them for sure, but they should work great for 500 yards and closer.

I'm pretty happy with the results. I have to do more shooting with the Remingtons to make sure that I can live with them, and also to get velocity data for a drop chart. Looking over past targets and data shows them to be really solid performers, which is funny to me because I have always hated Remington ammo of any kind. In my youth, if a rifle or shotgun was going to jam from ammo, or was going to shoot horribly, it was always, always with Remington ammo. I've gotten these rounds for as little as $11 a box, so it's win win for me apparently!

Look out Bambi, here I come!

9 comments:

mike's spot said...

I never had good luck pushing Core-Locts past 150-175 yards in my 270. Never did figure out what the heck I was doing wrong.

I'm thinking hard about a 308 Ar-10. . . what build did you go with?

Unknown said...

I went with a home brewed AR built on a DPMS upper and lower, with a Fulton Armory bolt and barrel--a 20" heavy match. Building them is super easy, but not as economical. You do get exactly what you want though. I'm going to probably switch to a Barnes bullet for handloading since they uaually have a cannelure.

mike's spot said...

I've built 223 ARs- but have never played with a 308. Free-float? It'll be a while- as I don't think its possible to touch a good 308 AR for under 1400 in my area.

Unknown said...

building a 308 AR is almost exactly the same as a 223 AR. Very minor differences.

If I had 1400 to spend on a 308, I could build one for that or probably less if I wasn't pressed for time. Easily.

I couldn't be thrifty with my 308 because I bought the lower a few months before the Obama election, and I was scrambling to find parts at any price. It was rediculous. It took like 3 months just to find a trigger - any trigger - to finish the lower.

A gunshow bought lower for a good price would be the way to start. DPMS has inexpensive barrels that are good to go; 85% of the accuracy that you would get with a high end barrel, easy. I absolutely recommend a FF tube as they are the best way to get accuracy out of the AR. These days they make nice sturdy ones for $100 new, sometimes less.

I'm going to do a 16" upper build very soon for this gun, as the 20" is heavy, and meant for shooting from the bench. With modern ammo, or good handloads, you can get amazing long range performance from the shorter barrel, and for hunting there's no reason not to.

mike's spot said...

Good to know- as the reason I was leery about the 16in was fear of loss of moderate range usefulness. the gun won't see more than 450 yards so I figured I was being picky- but its good to have my hunch reaffirmed that you can lose the 4 inches of tube.

Unknown said...

Oh yeah. There's an article on M4Carbine.net from one of the guys who helped develop the SR25EMC; he said with all the testing that Knight's did, the velocity only started dropping off with barrels less than 16", which is why they stopped with the 14" barrel.

Reading various forums and other reader's chrono results, I see about an 80 - 100 fps drop at the most from a 20" to a 16" barrel. Any deer sized critter within 600 yards won't know the difference, for sure. I've also read lots of articles and range reports of folks hitting steel at 1k with a 16" tube.

Unknown said...

I'm looking for that SR-25 EMC article right now. . . .

mike's spot said...

that is proof enough for me. I'll never complain about carrying a lighter rifle

Unknown said...

Here's a different thread from the same guy from Knight's - http://www.m4carbine.net/showthread.php?t=58669

Lots of real world chrono results. When I get a 16" built, I'll probably feed it some hot 110 grain HLs for 300 yards and closer.