In January my brother ordred a RRA A4, modified with heavy stainless target barrel, weaver gas block, and free floating. It finally arrived last Tuesday. He drove in from St. Louis to have me help him wring it and some handloads out ( he does not handload).
The first thing that I noticed was that the fit and finish seemed superior to most AR type rifles that I have personally handled. With that barrel it is very front heavy though. If it were my rifle, I would have the barrel fluted from one end to the other.
My brother has not decided on a permanent sighting system, yet. So he yanked a Nikon scope of some sort from one of his other guns and mounted it on this gun. I don't know what the exact model of scope or mount that he used. I do know that the scope went up to seven power.
I initially loaded up two types of rounds for him to try.
55 gr Rem FMJ , 24 gr H335, Rem brass, Rem 7.5 primer (trying to approximate M193 ammo)
60 gr A-Max, 24 gr Varget, Rem brass, Rem 7.5 primer.
We to it to the range and attempted to shoot the 55 grainers. Low and behold, we had a malfunction! The hammer went click--gun did not go boom. Had a heck of time extracting the round. I thought hmm, very tight chamber and or out of spec round.
All the other rounds fed and fired properly. Even the original went throught a second time with no apparent problems. I did find however, that during cease fires at the range, that more rounds were very hard to manually extract from the chamber.
I thought that this was odd because I used a Dillon guage to check the sizing of all of the rounds.
The gun proved to be very accurate at 25 yards with both types of ammo. We were just getting the scope on paper at this point. In fact, the scope was almost right on from the very beginning.
Moving out to 100 yards was very enlightening. The M193 clone ammo would put about10 rounds into a 1.5-2 inch group.
The A-Max loads on the other hand, frankly sucked. They would only put 3 rounds in to about an inch.
Oh, we put some factory WCC 94 M855 rounds through it also. They even grouped better than the A-Max loads.
The loads chrono's as follows. 55 gr FMJ avg 2925 fps(slow), A-Max 2766 fps, M855 3182 fps.
The 55 gr loads had a huge extreme spread of 125 fps and a lousy standard deviation of 47. Back to the drawing board.
The first thing I had to to was get the brass to chamber correctly. After much trial and error, I found the right setting for the size/trim die and the brass chambered easily. I had to push the shoulder back some more.
Round two: 55 gr, 25 gr H355, all else the same. 69 gr Sierra HPBT Match, 25 gr Varget.
Bingo, the 55 grainers still had a large extreme spread but the velocity was up to 3100 fps.
The 69 grainers grouped at about 1/2 of an inch at 100 yards and had a velocity of 2764 fps.
We abondonded the 60 gr A-Max for now. We may try something else later.
After the load development, we had a ton of fun just plinking with that heavy beast. We put about 300 rounds of the handloaded 55grainers through it yesterday. Needless to say, we went back to the house with smiles on our faces.
Excpt for that first round, the gun functioned flawlessly. It was quite easy to hit our targets while plinking.
This is the first time I have ever loaded for a semi-auto rifle. It turned out to be much easier than I thought it would be. I have loaded for bolt action rifles for about 20 years.
That frigging rifle is awesome! I can't wait to see what it can do with some tweaking of the loads.
BTW Only the 55 grain loads were crimped. As a test, we loaded up a 30 rounds mag with the 69 gr Sierra's and fire most of them. I then measured the length and compared it to the oringinal length of those rounds.
No change what so ever. I even chambered and unchambered a few several times and again measured them. The was no change in the length. I am no longer concerned with bullet set back with that load/rifle combination.
Now, if my Leitner-Wise rifle would get here I could have fun with my own AR type.