Poper
Member
I built a .243-6.5 WSSM on a Browning A-Bolt III .223 WSSM action several years ago. This project actually had a goal in mind: A short, light, quick handling rifle capable of .260 Remington performance out of a 19" barrel. I doubt I can get that kind of velocities out of a 19" barrel, but we will see.
The dang thing had feeding issues right off the git-go! I fiddled with it off and on for a couple years and, eventually, it found its way to the back of the gun safe.
In need of entertainment because my Sako 6.5x55 SM was getting boringly easy to work different loads up for it, I dug the 6.5 WSSM out of the safe.
I studied the dummies I had made up for the gun from new .25 WSSM cases years ago and then studied the drawings of the .243 WSSM and .25 WSSM. I already had a .243 WSSM and so elected to use .25 WSSM cases for the 6.5 WSSM to keep the two easily separate. The shoulder angles of the two are slightly different and probably account for the smoking of the 6.5 WSSM shoulders in the test loads that I fired years ago.
This time around, I decided to use new .243 WSSM cases from recent production cases. Fully prepped (sized, trimmed, chamfered, deburred, primer flashole deburred) and ready to load, I made up 3 dummies with Sierra 120 gr. GK's at 2.300" COAL. All chambered exceptionally tight. RCBS's Precision Mic indicated the shoulder set-back was .003", .005 and .006" for the 3 cases, so that wasn't the issue. I blackened the bullets and chambered them. All showed indications of striking the feed ramp but not jamming into the lands. I then blackened the necks and these showed marks indicating a too tight fit. A little trial and error with the Forster neck turning setup and things began working nicely by turning .003" off the outside diameter of the necks.
In my previous episode with the little gun I had used Berger 130 grain hunting bullets. The Sierra 120 gr. GK, is not so sharply pointed and is considerably shorter in length. I think this and maybe the .243 WSSM cases appear to have resolved the feeding issues. I have since turned all the new case necks and loaded up a batch of test loads with CCI-250 primers and IMR4350. 12 rounds ran through the magazine without a hitch. Saturday, weather permitting, I'll take her to the range and see if she will print a promising group.
The dang thing had feeding issues right off the git-go! I fiddled with it off and on for a couple years and, eventually, it found its way to the back of the gun safe.
In need of entertainment because my Sako 6.5x55 SM was getting boringly easy to work different loads up for it, I dug the 6.5 WSSM out of the safe.
I studied the dummies I had made up for the gun from new .25 WSSM cases years ago and then studied the drawings of the .243 WSSM and .25 WSSM. I already had a .243 WSSM and so elected to use .25 WSSM cases for the 6.5 WSSM to keep the two easily separate. The shoulder angles of the two are slightly different and probably account for the smoking of the 6.5 WSSM shoulders in the test loads that I fired years ago.
This time around, I decided to use new .243 WSSM cases from recent production cases. Fully prepped (sized, trimmed, chamfered, deburred, primer flashole deburred) and ready to load, I made up 3 dummies with Sierra 120 gr. GK's at 2.300" COAL. All chambered exceptionally tight. RCBS's Precision Mic indicated the shoulder set-back was .003", .005 and .006" for the 3 cases, so that wasn't the issue. I blackened the bullets and chambered them. All showed indications of striking the feed ramp but not jamming into the lands. I then blackened the necks and these showed marks indicating a too tight fit. A little trial and error with the Forster neck turning setup and things began working nicely by turning .003" off the outside diameter of the necks.
In my previous episode with the little gun I had used Berger 130 grain hunting bullets. The Sierra 120 gr. GK, is not so sharply pointed and is considerably shorter in length. I think this and maybe the .243 WSSM cases appear to have resolved the feeding issues. I have since turned all the new case necks and loaded up a batch of test loads with CCI-250 primers and IMR4350. 12 rounds ran through the magazine without a hitch. Saturday, weather permitting, I'll take her to the range and see if she will print a promising group.
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