About a week ago, I loaded 100 rounds of .357 Mag for my Ruger GP-100, and around the tenth round, it would not slide into the cylinder as expected. Several others did the same thing, so I stopped and two nights ago I tried inserting every remaining round to find 60 that would not drop in. They did not all stop at the same point. That led me to check the remaining 250 I had loaded some time ago.
Every one of them slid right into the cylinder.
After removing the decapping pin from the resize die, I pulled all the bullets and resized the cases with the powder still inside. Then, one by one, I dumped the powder into the digital scale pan and expanded the case mouths with my Lyman
Neck Expander, M-1 c-19, that has “38AP” on the tip of the expander ball. The cases all vary in length between 1.280 – 1.290, with most being around 1.284 or 5, and just a few less than 1.280. I varied the expander to just enough to start the bullet and a few out too far such that the seater die would not seat the bullet. The majority were expanded enough to start the seat.
What I did differently was seating the bullet and crimping in two separate procedures.
Aha! Problem solved! They were all sliding right into the cylinder as expected.
All except for 5 out of the 60…….!!!!
So the first question that arises is what happened when I seated and crimped simultaneously that caused the cartridges not to fit into the cylinder?
I just finished measuring those 5 cartridges, and I’ll summarize because I found that making a table doesn’t copy and paste as it should.
The cartridges range in COAL at 1.586 to 1.591” with the target being 1.590.”
The bullet is a Winchester 125gr JHP with a diameter of .357” (measured multiple times and confirmed with a digital micrometer; the Winchester bag just says (.38/357) at the base and .349” at the cannelure. The bullet alone drops into the GP-100 cylinder but stops at the exit with just the lead tip showing; all of the copper jacket remains in the cylinder. I have a Taurus 2-inch .38/.357 and these bullets drop completely through the cylinder.
The cases are nickel and are either RP or Win Western, resized many times, but no signs of cracked necks or loose primer pockets.
The cylinder of the GP-100 measures .377” at the entrance and .350” at the exit. Although there may be a discrepancy in my accuracy with a Lyman Digital caliper, the fact that the bullet does not fall out at the exit lead me to believe that maybe my COAL was too long, preventing the cartridges from chambering. But none of the 1.590” COAL loads that DO fit do NOT have the lead tip sticking out of the cylinder. They are all inside. So back to square one.
So, I measured the cases that would not chamber and compared the results to a cartridge case that DOES chamber.
The 5 misfits case range in OAL from 1.275” (1) to 1.290”. The three remainders are 1.284, 1.286 and 1.288. The case that DOES fit measures 1.276.
I measured each of them at the base, just under the case rim – all are either 0.379 or 0.380” including the case that fits. The mouth – with the bullet seated – also measures 0.375 to 0.380 except for the cartridge that fits; here it measured 0.376.”
Then I measured each case at 25%, 50% and 75% of the distance from the mouth of the cases, and they ALL measure 0.375” at 25% and 50%, and 0.380 at 75% (and just under the rim).
Then I inserted the cartridges that stick and measured the spot on the case where it stopped. There is no pattern other than they all stick after 50% of the cartridge is inserted (range 62% to 79% of the length of the case).
When I resize the cases, I always continue pushing the handle down until the shell holder maxes the excursion to just touching the die – not camming over at all, so I don’t think I’m failing to fully resize the case.
I also bought a headspace device made by Lyman that checks cartridges from .380 Auto to .45 ACP. ALL of the 60 failures that I had fit in that device.
I’m probably missing something simple, as often happens when one “overthinks” a situation. Any thoughts are appreciated.
Every one of them slid right into the cylinder.
After removing the decapping pin from the resize die, I pulled all the bullets and resized the cases with the powder still inside. Then, one by one, I dumped the powder into the digital scale pan and expanded the case mouths with my Lyman
Neck Expander, M-1 c-19, that has “38AP” on the tip of the expander ball. The cases all vary in length between 1.280 – 1.290, with most being around 1.284 or 5, and just a few less than 1.280. I varied the expander to just enough to start the bullet and a few out too far such that the seater die would not seat the bullet. The majority were expanded enough to start the seat.
What I did differently was seating the bullet and crimping in two separate procedures.
Aha! Problem solved! They were all sliding right into the cylinder as expected.
All except for 5 out of the 60…….!!!!
So the first question that arises is what happened when I seated and crimped simultaneously that caused the cartridges not to fit into the cylinder?
I just finished measuring those 5 cartridges, and I’ll summarize because I found that making a table doesn’t copy and paste as it should.
The cartridges range in COAL at 1.586 to 1.591” with the target being 1.590.”
The bullet is a Winchester 125gr JHP with a diameter of .357” (measured multiple times and confirmed with a digital micrometer; the Winchester bag just says (.38/357) at the base and .349” at the cannelure. The bullet alone drops into the GP-100 cylinder but stops at the exit with just the lead tip showing; all of the copper jacket remains in the cylinder. I have a Taurus 2-inch .38/.357 and these bullets drop completely through the cylinder.
The cases are nickel and are either RP or Win Western, resized many times, but no signs of cracked necks or loose primer pockets.
The cylinder of the GP-100 measures .377” at the entrance and .350” at the exit. Although there may be a discrepancy in my accuracy with a Lyman Digital caliper, the fact that the bullet does not fall out at the exit lead me to believe that maybe my COAL was too long, preventing the cartridges from chambering. But none of the 1.590” COAL loads that DO fit do NOT have the lead tip sticking out of the cylinder. They are all inside. So back to square one.
So, I measured the cases that would not chamber and compared the results to a cartridge case that DOES chamber.
The 5 misfits case range in OAL from 1.275” (1) to 1.290”. The three remainders are 1.284, 1.286 and 1.288. The case that DOES fit measures 1.276.
I measured each of them at the base, just under the case rim – all are either 0.379 or 0.380” including the case that fits. The mouth – with the bullet seated – also measures 0.375 to 0.380 except for the cartridge that fits; here it measured 0.376.”
Then I measured each case at 25%, 50% and 75% of the distance from the mouth of the cases, and they ALL measure 0.375” at 25% and 50%, and 0.380 at 75% (and just under the rim).
Then I inserted the cartridges that stick and measured the spot on the case where it stopped. There is no pattern other than they all stick after 50% of the cartridge is inserted (range 62% to 79% of the length of the case).
When I resize the cases, I always continue pushing the handle down until the shell holder maxes the excursion to just touching the die – not camming over at all, so I don’t think I’m failing to fully resize the case.
I also bought a headspace device made by Lyman that checks cartridges from .380 Auto to .45 ACP. ALL of the 60 failures that I had fit in that device.
I’m probably missing something simple, as often happens when one “overthinks” a situation. Any thoughts are appreciated.