So today's exercise was to make some loads for this new RAP using AR-Comp and, primarily, 123 SST's. Plus a few 120 gold dots. I have the RAP mounted in my LSS-xl MDt chassis. I'm getting to like it, 'course I figured I would!
I chose a load range close to others that have been successful in 16-20" barrels I have and have had, basically 27.8-28.4ish.
This Ruger I loaded ARC of 27.8, 28.0, 28.2, and 28.4, sst's at 2.265.
I also loaded 3 120 gold dots at 28.0 and 2 at 28.2 (that was the extent of ready brass I had). All Hornady brass and cci450 primers. The goldies set at 2.270
This barrel is fast. At least, to me!
SST's:
27.8: Avg 2554 SD 9.4
28.0: Avg 2558 sd 9.7. This threesome had ~0.3" clover but the magnetospeed was on the barrel so I don't really count it group-wise.
28.2: Avg 2569 sd- 20.7 (one outlier of 2593 ft/s - no idea why).
28.4: Avg 2578 sd-7.3. This group showed some definite beginnings of primer craters.
For the gold dots, the 28.0's averaged to 2617, sd 7.0, and the 2 at 28.2, for 2641 avg.
The 28.2 for these definitely have some primer craters but edges look round. I doubt I would stay at this load or go higher, probably limit myself to 28.0.
Now I don't put a lot of stock into the quoted sd's since the groups are very small, but I do think I have some potential at 28.0-28.2 for the SST and 28.0 for the gold dots.
I have my PA 4-14x44 scope on it, and like how it's performing on this rifle so far.
Makes them loads I would feel comfortable using out to 275 or maybe 300 yds if the shot and the deer were good.
as a footnote I have a couple of ASC mags inbound, due to comments from other RAP-users. (Rappers? lol!!)
"Down the floor, out the door, Go Brandon Go!!!!!"
Those are some impressive velocities. I havent sent too much time playing with ARC, but I do know my howa maxes out at about 2500 with Benchmark and the 123 SST. I have not really played with the Gold Dots much yet, but i just might with ARC to see if I can come close to your results. I need to find my QL print out again.
I credit some of this to my prep upon receipt. I have (and had) several of the Predator barrels doing the same to all - and you want to remove some of the internal friction (comes pretty standard in a rack grade barrel) by polishing the insides with some JB bore cleaning compound. Do 2 or 3, 1 3/4" swabs (for the 6.5's anyway) with it on there and run them back and forth in the barrel to smooth down the "innards", then clean it out with Kroil or cleaner of your choice, and a little light oil... less internal friction means more powder energy goes into bullet acceleration. I was expecting more like 520 or so but IMO the bore treatment adds 25-50 ft/s to final MVs.
"Down the floor, out the door, Go Brandon Go!!!!!"
grayfox Wrote:So today's exercise was to make some loads for this new RAP using AR-Comp and, primarily, 123 SST's. Plus a few 120 gold dots. I have the RAP mounted in my LSS-xl MDt chassis. I'm getting to like it, 'course I figured I would!
I chose a load range close to others that have been successful in 16-20" barrels I have and have had, basically 27.8-28.4ish.
This Ruger I loaded ARC of 27.8, 28.0, 28.2, and 28.4, sst's at 2.265.
I also loaded 3 120 gold dots at 28.0 and 2 at 28.2 (that was the extent of ready brass I had). All Hornady brass and cci450 primers. The goldies set at 2.270
This barrel is fast. At least, to me!
SST's:
27.8: Avg 2554 SD 9.4
28.0: Avg 2558 sd 9.7. This threesome had ~0.3" clover but the magnetospeed was on the barrel so I don't really count it group-wise.
28.2: Avg 2569 sd- 20.7 (one outlier of 2593 ft/s - no idea why).
28.4: Avg 2578 sd-7.3. This group showed some definite beginnings of primer craters.
For the gold dots, the 28.0's averaged to 2617, sd 7.0, and the 2 at 28.2, for 2641 avg.
The 28.2 for these definitely have some primer craters but edges look round. I doubt I would stay at this load or go higher, probably limit myself to 28.0.
Now I don't put a lot of stock into the quoted sd's since the groups are very small, but I do think I have some potential at 28.0-28.2 for the SST and 28.0 for the gold dots.
I have my PA 4-14x44 scope on it, and like how it's performing on this rifle so far.
Makes them loads I would feel comfortable using out to 275 or maybe 300 yds if the shot and the deer were good.
as a footnote I have a couple of ASC mags inbound, due to comments from other RAP-users. (Rappers? lol!!)
28.2 arcomp and 120 gold dots at 2.270 ended up being my sweetheart load for both my 16 inch and 12.5 inch ar grendels.
No primer cratering only pressure signs is a very light ejector mark. Does 2484 and 2421 average from my barrels.
I need to see what my CZ can do with this bullet. Like your rap my CZ is fast very fast.
I'm using an MDT Lss-xl stock for the RAP, it has an AR-mag lower magwell. And a Magpul CTR-with 0.75 snap-in cheek riser, magpul K2+ grip. Vg6 6.5 Gamma MB. PA 4-14x44 ffp scope. Shooting 100 yds indoors from a bench.
I took it out this evening with some hand loads of 123 SST's and 120 Gold's.
Powder is AR Comp, cci 450 primers.
for the Sst, 27.8 (2558 ft/s) and 28.0 (2569 ft/sec), 2.265 Oal. For the gold dots, 28.0 (2617 ft/s), 2.270 Oal.
Center, SSt 27.8, the obligatory Stonehenge (first shot), then a good 3-group. Lower Left, the 28.0 Sst, 4-group. The lower right, 120 Gold Dot, 2617, I think I fidgeted (eye lost focus) the first 2 (lower left and lowest) the other 2 were good holds. Still not too bad.
As to feeding, I used my Asc mag exclusively, and it fed fine for all but the final rounds in each mag. 1 final one fed, 2 I was able to re-feed by pulling the bolt back and then push ok, 1 totally ftf, I had to manually position it. Out of 16 shots total (there's also 1 group of 4 Sst upper Left 28.2 Ar Comp I already had for a separate rifle).
2 Pics, One shot at the range and 1 with labels added, at home.
[ATTACH=CONFIG]15495[/ATTACH]
[ATTACH=CONFIG]15496[/ATTACH]
"Down the floor, out the door, Go Brandon Go!!!!!"
