milkman
05-21-2022, 06:56 PM
I hope this will help someone else who is having failure-to-fire problems.
I decided that I REALLY NEEDED a rifle in 7 T/CU. I don't believe there are any factory bolt rifles in that caliber so.....
I bought a Savage Axis rifle for a donor action. I got a Shilen 24” 1:12 twist barrel pre-chambered in 7mmT/CU and had a smith mount everything in a Boyd's walnut stock. I did not have, and could not find any go, no-go gauges so I took some 223 brass, which is the parent cartridge, ran a 35 cal expander into it, which left a straight wall, straightish wall, case. Then ran it into a 7 t/cu full length die seated against the shell holder and backed off slightly and the gunsmith used these cases to head space the barrel.
While waiting on the smith to finish the rifle I prepared more cases by running 223 cases into the 7 t/cu die to expand the neck and use the existing shoulder till it was fire formed to the chamber then cast up some Lee 130g soup can boolits that have shot well for me in other rifles. When the rifle was delivered I loaded some cases and seated the cast bullets long so they would be forced into the rifling to hold the case in place while fire forming. Everything looked good but I had a FTF in about 1 in 10 rounds. The primer was dimpled and on some of the removed primers the anvil had backed out of the cup.
I checked the primers and they were standing proud of the case. I was using a primer arm that was new and it just wasn't seating the primers fully. Problem solved!! NOT
FTF's about I in 8...I changed primer brands and had a couple of decades worth of manufacture dates in different brands. No help.
I disassembled the bolt and checked, cleaned, lubed everything. No help. I took the bolt from another Axis, swapped the bolt heads and tried again. No help. After a couple months of hair pulling and teeth grinding my son loaned me his fancy-schmancy case length gauge which measures to a shoulder datum. The 223 cases which I had only expanded the neck on were about .030” shorter than my chamber as measured on the longest cases. Even after fire forming with a cast bullet some were still .020” short. They had enough extra room in the chamber to invite friends for a sleepover.
I went through all 100+ cases that I had formed, pulled all that were over .005 shorter than the longest cases. On those I expanded the necks to 35 cal and then back through the full length sizing die set to about .002 below fired length. No more FTF's
Milkman
I decided that I REALLY NEEDED a rifle in 7 T/CU. I don't believe there are any factory bolt rifles in that caliber so.....
I bought a Savage Axis rifle for a donor action. I got a Shilen 24” 1:12 twist barrel pre-chambered in 7mmT/CU and had a smith mount everything in a Boyd's walnut stock. I did not have, and could not find any go, no-go gauges so I took some 223 brass, which is the parent cartridge, ran a 35 cal expander into it, which left a straight wall, straightish wall, case. Then ran it into a 7 t/cu full length die seated against the shell holder and backed off slightly and the gunsmith used these cases to head space the barrel.
While waiting on the smith to finish the rifle I prepared more cases by running 223 cases into the 7 t/cu die to expand the neck and use the existing shoulder till it was fire formed to the chamber then cast up some Lee 130g soup can boolits that have shot well for me in other rifles. When the rifle was delivered I loaded some cases and seated the cast bullets long so they would be forced into the rifling to hold the case in place while fire forming. Everything looked good but I had a FTF in about 1 in 10 rounds. The primer was dimpled and on some of the removed primers the anvil had backed out of the cup.
I checked the primers and they were standing proud of the case. I was using a primer arm that was new and it just wasn't seating the primers fully. Problem solved!! NOT
FTF's about I in 8...I changed primer brands and had a couple of decades worth of manufacture dates in different brands. No help.
I disassembled the bolt and checked, cleaned, lubed everything. No help. I took the bolt from another Axis, swapped the bolt heads and tried again. No help. After a couple months of hair pulling and teeth grinding my son loaned me his fancy-schmancy case length gauge which measures to a shoulder datum. The 223 cases which I had only expanded the neck on were about .030” shorter than my chamber as measured on the longest cases. Even after fire forming with a cast bullet some were still .020” short. They had enough extra room in the chamber to invite friends for a sleepover.
I went through all 100+ cases that I had formed, pulled all that were over .005 shorter than the longest cases. On those I expanded the necks to 35 cal and then back through the full length sizing die set to about .002 below fired length. No more FTF's
Milkman