rockrat
10-03-2009, 11:42 PM
Been trying different loads and have a good 5 shot group and then the next are all over the place. Some show promise and some were in the toilet. Went out this morning as I had tried some loads with 5010 and a piece of dacron on top of the powder, they showed promise, but also the velocity jumped 200fps. Hmmm.
Wondering about boolits sealing @.512, so went to a .513" size die. Tried to seat boolits and was getting weird seating depths. Come to find out, the crimping portion of the seating die was only about .5125" in diameter and was catching the boolit, giving odd seating depth.
Higher velocity loads were giving larger groups, so figure maybe 2400fps or less was a velocity threshhold for the AR50. It has a rifling like the Marlin micro-groove barrels. Shallow rifling, so thinking boolits may be skidding. Went back to loading bench and lowered charge of 5010 and also WC860. Trying for 2300fps or so. 5010 would shoot first shot high, then 3 about 3" lower in 1.5"-2" groups. These are the upper groups, only difference is left group has boolit seated to crimp groove, right group has boolit seated about .100" off max. OAL. Velocity was 2226fps.
Lower group was the wc-860 (never had a decent group with this). First shot was about 2" above POA, the second was about 1" above that (Bench technique to fault), then two close to first. Fifth shot I expected to be out of group as round chambered somewhat snugly--sure enough, was low. Sixth and seventh were below fourth. Final group, taking out the expected flyers, was about 1.5" for the 5 shots. Velocity was 2430fps 11,170 ft-lbs
Going to play a bit more with the wc860, but have some H869, which is alot slower. Maybe an easier acceleration might help with higher velocity loads. If not, then will wait till I get my ALS bolt back, and start working with that gun as it has a Pac-Nor barrel with 6 land/groove rifling.
http://i34.photobucket.com/albums/d149/Bigdog337/006-1-1.jpg
Wondering about boolits sealing @.512, so went to a .513" size die. Tried to seat boolits and was getting weird seating depths. Come to find out, the crimping portion of the seating die was only about .5125" in diameter and was catching the boolit, giving odd seating depth.
Higher velocity loads were giving larger groups, so figure maybe 2400fps or less was a velocity threshhold for the AR50. It has a rifling like the Marlin micro-groove barrels. Shallow rifling, so thinking boolits may be skidding. Went back to loading bench and lowered charge of 5010 and also WC860. Trying for 2300fps or so. 5010 would shoot first shot high, then 3 about 3" lower in 1.5"-2" groups. These are the upper groups, only difference is left group has boolit seated to crimp groove, right group has boolit seated about .100" off max. OAL. Velocity was 2226fps.
Lower group was the wc-860 (never had a decent group with this). First shot was about 2" above POA, the second was about 1" above that (Bench technique to fault), then two close to first. Fifth shot I expected to be out of group as round chambered somewhat snugly--sure enough, was low. Sixth and seventh were below fourth. Final group, taking out the expected flyers, was about 1.5" for the 5 shots. Velocity was 2430fps 11,170 ft-lbs
Going to play a bit more with the wc860, but have some H869, which is alot slower. Maybe an easier acceleration might help with higher velocity loads. If not, then will wait till I get my ALS bolt back, and start working with that gun as it has a Pac-Nor barrel with 6 land/groove rifling.
http://i34.photobucket.com/albums/d149/Bigdog337/006-1-1.jpg