Speaking of 200 to 225 grain bullets, I made it to the range last weekend to test my 200 grain XPBs and 225 grain COP bullets over factory primed and charged brass. I was shooting for function, so didn't chrono any of the rounds, nor did I measure groups. I wont go into a blow by blow of my results, but feel free to ask of anyone has any questions.
I loaded 5 rounds of each bullet. All were fired at 100 yards from my Bushmaster 16" upper. I had sighted in at 2 inches high at 100 yards with factory 250 grn FTX before firing the test rounds. The 5 shot factory group printed at about 1 3/4 inches from the bench with a bipod and sandbag beneath the heel of the butt. (next time I plan to fire more than 20 rounds from the bench, I'm taking my Lead Sled) Here are my general observations:
Barnes 200 grain XPB
- All 5 rounds showed less than .002" expansion of the case base
- Shots 1, 3 and 4 had heavy sooting all the way to the rim of the case and the cases ejected between the 2 and 3 o'clock positions.
- Shots 2 and 5 both had minor sooting around the case mouth, and both ejected to the 7 o'clock position. I experienced a hang fire on shot #2 - it went click-bang.
- Four of the five shots were grouped at about one and one half inches with the remaining shot being about an inch low of the group - I expect that one was the hang fire shot. The 4 shot group printed at 3 inches high.
General Bullet 225 grn C.O.P. hollow points
- All 5 rounds showed .001" or less case base expansion
- All 5 cases had minor sooting around the case mouth
- All 5 cases ejected between the 2 and 3 o'clock positions
- Group size was about 2 inches and about 2 1/2 inches high. (this group was comprised of shots 20 through 24 for the day, so I am sure I wasn't performing my best by that time.)
All in all, I am happy with the results. For having only 30 rounds through the rifle, the accuracy is already acceptable. I'd like to tune up the 200 XPBs to reduce the sooting and achieve the best results I can safely get, but I'll have to wait for the new chrono before doing so. (BTW, I checked for other pressure signs after every shot and found none. All primers were slightly flattened, but virtually identical to those of the unmodified factory rounds).