Reloads and Chamber Fit

[Headhog]

At pawn/gun shop nearby, they had several Taurus GX4's in the case. The price was right and it felt good in my hand so, I did the paper work and brought it home. We'll I promptly loaded each magazine (comes with 2) with 5 rounds of factory 9mm and 5 rounds or my go to 9mm reload. Then proceeded out my basement to test fire the GX4. The Factory ammo was Sellier & Bellot 124gr. FMJ RN and my reloads are cast 124gr. Acme HiTek coated RN. The S&B fired and function perfectly, but my reloads would not go fully into battery.

So back to the basement reloading room and see what is going on. Turns out the ogive of the Acme bullet and the factory round are slightly different. Both bullets are loaded to the exact same COL but because of the different ogives, my reloads will not fully chamber in the GX4. So I decided to share some thoughts and pictures to demonstrate how important it is to chamber check your reloads in every firearm you plan to shoot them in.

The first picture below shows the two rounds in a caliper showing their length. They both are at 1.158", which is well within the SAAMI spec. of 1.00"-1.169".

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So I decided to show how these fit into the chambers of several 9mm pistol barrels. Below are 4 of my 9mm pistol barrels each with a round in the chamber. From left to right are my STI-Trojan (1911 9mm), Glock 43, Glock 17 and the Taurus GX4. This first picture has the S&B round in each barrel.

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This last pictures shows the fit of my reload with the Acme bullet. You can clearly see how my reload sits proud of the chamber hood in the GX4 barrel.

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What I wanted to show here is how important it is to make sure our reloads fit and function in our firearms. Even thought my reload is a time and function tested round, it's not good for the GX4. Is the GX4 a problem? Is it chambered wrong? I don't think so, since I also tried some Hornady Critical Defense rounds that functioned perfectly in the GX4. It's just that when reloading some component selections don't work in all firearms.

So what are my options. These Acme bullets are one of my all time favorite bullets. Over the last 5 years I've fired close to 9,000 rounds of these reloads. I use them for everyday range shooting and competition. Since I don't plan to change bullets, anytime soon, I'll have to experiment with seating these bullets deeper. My hope is that in seating the bullets deeper these reloads will continue to function as flawlessly, in all my 9mm pistols, as the do at the 1.158" length. I don't want to keep different reloads for different firearms. I want one size that fits all.

Paul

[Cofisher]

Thanks for your report. I have used only 2 or 3 types of bullets in my loading. Have not run into this. I will be watching more carefully.

[John E Davies]

Do you already use a Lee Factory Crimp Die? If not, get one and see if it solves your problem. it resizes the entire round all the way to the head rather than just at the mouth.

https://www.amazon.com/LEE-PRECISION-9 ... B000O7HCK0

If that doesn’t fix it, then you can explore deeper seating.

John Davies
Spokane WA

[Mags]

...

In your first picture showing OAL, I see more case swelling in your reload below the case mouth than in the factory ammo. Something to consider.

[Headhog]

...

In your first picture showing OAL, I see more case swelling in your reload below the case mouth than in the factory ammo. Something to consider.

Good to consider all possibilities, but this is only a product of poor lighting for the photo. One overhead light can produce strange glare and shadows in strange places. Just in case this might be the problem, I pulled a dozen of the offending reloads and checked the cases with a caliper. Measured at the case mouth and just below where the bullet base would be, they measure within SAAMI specs.

The other consideration is that I use a carbide sizing die in a progressive press. Carbide dies tend to make cases like 9mm take on an hour glass contour. Wider near the case mouth to bullet base and then taper in below the bullet base. This effect may also be what you are seeing in the first photo.

Paul

[Headhog]

Do you already use a Lee Factory Crimp Die? If not, get one and see if it solves your problem. it resizes the entire round all the way to the head rather than just at the mouth.

https://www.amazon.com/LEE-PRECISION-9 ... B000O7HCK0

If that doesn’t fix it, then you can explore deeper seating.

John Davies
Spokane WA

John that is certainly a valid option and I do have that die. I found it made no difference in my 9mm loads. I retired that die to the back of my reloading die draw. Reloading in a progressive press I chose to go with a RCBS powder check die in the 4th station. I felt it was more important to know if I had a double charge of squib. As I mentioned in another post, I also checked final cartridge dimensions against SAAMI specs.

Paul

[JVogler]

Had the same problem with my reloads,only 147 grain fp would fit into my brothers S&W m&p sheild. Bought an 8 caliber Lyman cartridge checker gauge all my cartridges fit into said case checker. Got out a Ruger convertible 9mm chamber and same cartridges wouldn't fit revolver. Adjusted Lee factory crimp die another turn and ran my finished 9mm rounds through crimp die again. About 98 percent now fit the Ruger cylinder. Will test fire some rounds tomorrow.

[fortyshooter]

I have a Wilson chamber check gauge that I use when checking my 45 ACP loads. If round doesn't drop in flush something is wrong. What that wrong usually is is that for some reason a bullet gets seated slightly off center resulting in a case bulge more on one side. Sometimes I can fix that by chucking the round in the drill press and lightly polish it with 320 grit paper. Now sometimes it can be a burr or issue with the case head which you can fix same way. The round should drop right in the chamber gauge or barrel chamber flush.
That new pistol may have a slightly tighter chamber diameter than the others.

[Headhog]

This morning I put together some new reloads to test out the performance of the GX4. I shortened up my reloads to 1.115" so that the rounds would drop into the barrel chamber and fit flush with the barrel hood.

At the range loaded up the magazines fully with 11 rounds. Running the first 2 magazine through I experienced a few failures of the slide to return completely to battery. A slight tap on the back of the slide and the GX4 was ready to go. After 5 magazines this problem disappeared. I attribute this to break-in of a new gun and magazines.

Next to test this same loads in my other 9mm guns, but I really don't expect any issues.

Paul

[PJM]

Had similar problems with reloads for S+W .40 MP 2.0. Factories were perfect for multiple manufacturers. Reloads not so much. Appears to be burrs on case mouth crimp. Run finger down reloaded bullet and see if you feel the edge. Then do the same for a factory round and see if different. I started outside chamfering after tumbling before resizing and problem improved significantly. Will eventually purchase a lee factory die as others suggest.