Mark 4 T to Range for load development

Went to the range today to shoot rifle with load tests. Chronographed 4 powders in new and fired cases trying to see if there was an appreciable difference in velocity. Used 2 brands of new ammo to find base for store bought ammo. From Sellier & Bellot 180 FMJ had 2344 velocity. Prvi 180 SP 2370 and 2346 fps. My loads were a 174 SMK using H4350 Reloader 17 Reloader 15 and Varget. Started at 43 g. H4350 at 2170 with fired cases 2190 with new cases.
Ended at 44.5 g. 2322 for fired cases and 2334 for new cases. Reloader 17 at 45.5 grains gave me 2425 avg. for just two rounds in fired cases and 2423 in new cases. Reloader 15 at highest weight 41 g. gave 2328 in fired cases and Varget at 41 g. gave 2335. I used CCI Large Rifle Primers and a Lee Collet die to size the neck only. I sized the new cases so they wouldn't be as tight and cleaned the primer pockets. I did not check runout necks or case weights and my OAL with the Sierra bullets was 3.035 + or -. I tried to use a modified case to find the lands but they were too far away. When I can get the 180 Sierra flat base I might find them but the boattail bullets didn't reach. After shooting through the chronograph I shot our 18 inch gong at 600 yards. Close but no cigar. Still trying to shoot this 3.5x scope and get correct sight picture. Took shot at 1000 yards and was 50 feet short of target with dialup at 10. To shoot at 100 yards the scope dial is on 2 so that might be the cause of my shortfall. I include the test target and picture of the sweet Mark 4 T . As a side note it is fantastic to have the members knowledge to help my entry into Enfield shooting. Attachment 23119Attachment 23118Attachment 23117

Thanks for the write up!

Any powder preference yet? Or are you still in the bullet selection phase?

I've been meaning to work up some loads using IMR 4007SSC, but have been on other projects recently. Have been using IMR 4064 with good results, but the pressures run higher than the 4007, so...

Thanks for the check. I thought the Reloader 15 shot well but the case was not used to capacity. The Reloader 17 was good fill with good results. other than the usual pressure checking via primer check, bolt tightness and velocity I don't have way to check pressure. I shoot R 17 in two other calibers and like how it works. I have 180 flat base Sierras coming so will test the R17 with this bullet. Will also try the IMR 3031. I tend to find a powder in my vicinity and shoot till I can't get better. This avoids having too many partial cans of powder around. Am painting some foam board to make targets to match 3 and 600 yard targets so will "get to" sighting for those ranges with 174 sierra and 180 Sierra, when results are in I will post again

IMR 3031 is to hot. Varget is the one i use

Varget is good or if available the VV N140 is a good choice for the .303 . Has my best results with it and a 180grs FMJBT bullet. Nice rifle!