Boz330
01-01-2018, 02:27 PM
This round has been a REAL education to say the least and it isn't finished yet. I got the rifle 1-1/2 weeks before deer season and really wanted to use it. I worked up a load for a 325gr mold that I already had and zeroed the sights just in time to hunt with it. The hunt was successful but some of the rounds that I had loaded were difficult to chamber but I didn't have time to figure that out before season.
After season I started working on a competition load for this rifle. Since I have owned a number of 40-65s over the last 20+ years I had plenty of molds to try. The first thing I ran up against was chambering problems with molds that didn't have reduced front driving bands to fit up into the bore so I sized to .408 instead of .409 and this helped a little but didn't solve the problem of having to use a cam stick on some rounds, while others chambered with no problems. Groups at 300yd would have several rounds in almost MOA groups and then flyers 12" to sometimes 18" out of the group. These rounds were showing some bullet tipping to. I don't profess to be a terrific marksman but I sure wasn't seeing sight pictures that bad. I was also getting hard extractions on the rounds that required the cam stick. After that shooting session I had to go back to the drawing board for sure.
When I got back to the house I got the caliper out and started doing some measuring of the cases and low and behold the inside neck diameters on some of the cases were .403 and .404 instead of .408 and above. Outside neck diameters were .433 to .434 which is about as they should be. These cases were formed form 30-40 cases which is what Kirk at Shiloh suggested using. When I went looking for those cases I found that they really aren't all that available and the only ones around were Graf's cases so I ordered 2 bags of 50 to start with and fire formed them.
After thinking I had solved the problem I ordered a .410 Forster neck reamer to open the neck of the fired cases. I had to make a special fitting for my Lyman case trimmer to ream the necks but got the job done. What I found in the process was that the case thickness varies greatly on these particular cases. Some didn't hardly need reaming and others were a real chore to get to size. So some bullets were either being sized down in seating or expanding the case in the process of seating making those rounds hard to chamber. All of which would make for erratic variances in velocity and bullet fit. Since I had 2 different bags of brass from the same manufacturer and they were mixed I can't be sure that accounted for all of the differences.
I also have 2 bags of Winchester 303 brass that can also be used for the parent case but am holding off till I see how the reamed 30-40 brass does.
I do have a question for you guys about case trimmers though. Is there a good power case trimmer that any of you can recommend. I have seen reviews that say they don't hold accuracy very well. My hands after reaming and/or trimming 100+ cases are toast not to mention deburring inside and outside:cry:. Thanks
Bob
After season I started working on a competition load for this rifle. Since I have owned a number of 40-65s over the last 20+ years I had plenty of molds to try. The first thing I ran up against was chambering problems with molds that didn't have reduced front driving bands to fit up into the bore so I sized to .408 instead of .409 and this helped a little but didn't solve the problem of having to use a cam stick on some rounds, while others chambered with no problems. Groups at 300yd would have several rounds in almost MOA groups and then flyers 12" to sometimes 18" out of the group. These rounds were showing some bullet tipping to. I don't profess to be a terrific marksman but I sure wasn't seeing sight pictures that bad. I was also getting hard extractions on the rounds that required the cam stick. After that shooting session I had to go back to the drawing board for sure.
When I got back to the house I got the caliper out and started doing some measuring of the cases and low and behold the inside neck diameters on some of the cases were .403 and .404 instead of .408 and above. Outside neck diameters were .433 to .434 which is about as they should be. These cases were formed form 30-40 cases which is what Kirk at Shiloh suggested using. When I went looking for those cases I found that they really aren't all that available and the only ones around were Graf's cases so I ordered 2 bags of 50 to start with and fire formed them.
After thinking I had solved the problem I ordered a .410 Forster neck reamer to open the neck of the fired cases. I had to make a special fitting for my Lyman case trimmer to ream the necks but got the job done. What I found in the process was that the case thickness varies greatly on these particular cases. Some didn't hardly need reaming and others were a real chore to get to size. So some bullets were either being sized down in seating or expanding the case in the process of seating making those rounds hard to chamber. All of which would make for erratic variances in velocity and bullet fit. Since I had 2 different bags of brass from the same manufacturer and they were mixed I can't be sure that accounted for all of the differences.
I also have 2 bags of Winchester 303 brass that can also be used for the parent case but am holding off till I see how the reamed 30-40 brass does.
I do have a question for you guys about case trimmers though. Is there a good power case trimmer that any of you can recommend. I have seen reviews that say they don't hold accuracy very well. My hands after reaming and/or trimming 100+ cases are toast not to mention deburring inside and outside:cry:. Thanks
Bob