wv109323
05-30-2014, 09:56 PM
This will be a long post so the problem up front is : I have a Mi-hec mold that I can not get to shoot with any accuracy .
My goal is to develop a load to be used for the NRA Distinguished revolver competition with slow fire targets at 50 yards. My anticipation is accuracy of 2 1/2" at fifty yards or better.
Here are the things in common to the problem:
Firearm is a S&W model 14-6 with a 6" full lug barrel with probably less than 3000 rounds.
All primers used were Winchester Small pistol.
Brass was misc. mixed and not trimmed.
Loading was done on a Star Progressive and RCBS single stage for some of the small test lots.
All boolits were sized in a Star lube-sizer with Red Carnuba or 2500 from Whites. The nominal size was .358 and the boolits came out at .3577. The forcing cones of the cylinder are very consistent at .3572.
All testing was done with a Ransom rest at 52 yards.
I slugged the bore and could not measure diameter due to the odd number of rifling in a S&W barrel but the boolits showed good engraving in the rifling.
There was very,very little leading of the barrel observed with any of the loads.
Bullet alloy was wheel weights(clip-on) mixed with range scrap from a Bulleye pistol range.
All cast boolits were from a Lyman 20 lb. bottom pour pot with PID controls.
All boolits were rolled crimped in the crimping groove.
Casting temps were 700 to 730 degrees. Molds were preheated on a hot plate.
Here are the variables:
Powders- Bullseye- WST- WW231
Molds as follows
RCBS 2 cavity 358 158 round nose flat base-steel
NEI- 2 cavity 358 158 SWC with a radius base- Aluminum
Mi-Hec- 4 cavity 360 158 SWC flat base- Brass
The RCBS boolits as cast were .3577 to .3583 and weighed 156 to 154.5 gns.
The Mi-hec boolits as cast were .3603 to .3608 and the latest bullets weighed 155 to 154 gns. The earlier cast boolits were less uniform but still 155 to 151 gns. I had a learning curve( lead and mold temp.) with the Mi-hec brass mold.
Here are the group sizes fired by mold:
Factory rounds:
Magtech 158 gn LRN 5 rounds in 2 1/2"
Remington 158Gn. LRN 6 rounds in 3 5/8" with 4 rounds in 1 1/4"
NEI mold:
3.2 gn. BE 10 rounds 5 1/2"
4.5 gn. of WW231 9 rounds 2 1/4" with 8 rounds in 1 5/8"
4.5 gn. of WW231 10 rounds 2 1/2" (retested to confirm results)
RCBS-RN mold
4.1 gn. of BE 10 rounds 4 1/4"
3.2 gn. of BE 10 rounds in 4" with 9 rounds in 3"
3.5 gn. of WST 10 rounds in 1 15/16"
Mi-Hec mold
4.5 gn. of WW231 10 rounds in 16"
3.5 gn. of WST 10 rounds fired, 8 rounds in 13 1/8" and 2 rounds off the paper(?)
3.5 GR. of WST 9 rounds fired, 7 rounds in 12" and 2 rounds off the paper
4.2 gn. of BE 10 rounds fired only 4 rounds on the paper
Does anybody have any idea of my problem with this mold? I thought at first it was the quality of my cast boolits but the last boolits were as good as I have ever cast. Bases were very flat, weights were consistent. There was no resemblance of a "group" with many of these loads. There may be 4" between any two shots. The 3.5 gn. of WST had 5 rounds within 2 3/4" but that was it. The other two molds had good results with the proper powder charge.
The only thing I can come up with is the .360 diameter is allowing the rifling to "smear" lead down the side of the boolit and the base of the bullet has a small fin that corresponds to each rifling in the barrel.
I appreciate any comments. I hate to have a mold that I can not use, especially since I bought a 4 cavity to reduce my casting times.
My goal is to develop a load to be used for the NRA Distinguished revolver competition with slow fire targets at 50 yards. My anticipation is accuracy of 2 1/2" at fifty yards or better.
Here are the things in common to the problem:
Firearm is a S&W model 14-6 with a 6" full lug barrel with probably less than 3000 rounds.
All primers used were Winchester Small pistol.
Brass was misc. mixed and not trimmed.
Loading was done on a Star Progressive and RCBS single stage for some of the small test lots.
All boolits were sized in a Star lube-sizer with Red Carnuba or 2500 from Whites. The nominal size was .358 and the boolits came out at .3577. The forcing cones of the cylinder are very consistent at .3572.
All testing was done with a Ransom rest at 52 yards.
I slugged the bore and could not measure diameter due to the odd number of rifling in a S&W barrel but the boolits showed good engraving in the rifling.
There was very,very little leading of the barrel observed with any of the loads.
Bullet alloy was wheel weights(clip-on) mixed with range scrap from a Bulleye pistol range.
All cast boolits were from a Lyman 20 lb. bottom pour pot with PID controls.
All boolits were rolled crimped in the crimping groove.
Casting temps were 700 to 730 degrees. Molds were preheated on a hot plate.
Here are the variables:
Powders- Bullseye- WST- WW231
Molds as follows
RCBS 2 cavity 358 158 round nose flat base-steel
NEI- 2 cavity 358 158 SWC with a radius base- Aluminum
Mi-Hec- 4 cavity 360 158 SWC flat base- Brass
The RCBS boolits as cast were .3577 to .3583 and weighed 156 to 154.5 gns.
The Mi-hec boolits as cast were .3603 to .3608 and the latest bullets weighed 155 to 154 gns. The earlier cast boolits were less uniform but still 155 to 151 gns. I had a learning curve( lead and mold temp.) with the Mi-hec brass mold.
Here are the group sizes fired by mold:
Factory rounds:
Magtech 158 gn LRN 5 rounds in 2 1/2"
Remington 158Gn. LRN 6 rounds in 3 5/8" with 4 rounds in 1 1/4"
NEI mold:
3.2 gn. BE 10 rounds 5 1/2"
4.5 gn. of WW231 9 rounds 2 1/4" with 8 rounds in 1 5/8"
4.5 gn. of WW231 10 rounds 2 1/2" (retested to confirm results)
RCBS-RN mold
4.1 gn. of BE 10 rounds 4 1/4"
3.2 gn. of BE 10 rounds in 4" with 9 rounds in 3"
3.5 gn. of WST 10 rounds in 1 15/16"
Mi-Hec mold
4.5 gn. of WW231 10 rounds in 16"
3.5 gn. of WST 10 rounds fired, 8 rounds in 13 1/8" and 2 rounds off the paper(?)
3.5 GR. of WST 9 rounds fired, 7 rounds in 12" and 2 rounds off the paper
4.2 gn. of BE 10 rounds fired only 4 rounds on the paper
Does anybody have any idea of my problem with this mold? I thought at first it was the quality of my cast boolits but the last boolits were as good as I have ever cast. Bases were very flat, weights were consistent. There was no resemblance of a "group" with many of these loads. There may be 4" between any two shots. The 3.5 gn. of WST had 5 rounds within 2 3/4" but that was it. The other two molds had good results with the proper powder charge.
The only thing I can come up with is the .360 diameter is allowing the rifling to "smear" lead down the side of the boolit and the base of the bullet has a small fin that corresponds to each rifling in the barrel.
I appreciate any comments. I hate to have a mold that I can not use, especially since I bought a 4 cavity to reduce my casting times.