Resizing Shotgun Shells by John Bulger

My reloader is a MEC 9000GN in 28 gauge. I had made the assumption the resizer on this machine would resize to the proper specifications for the 28–gauge shell. You know what they say about “assuming!”

have been reloading rifle, pistol and shotgun ammunition for more than 25 years, but this article will not be about reloading machines or reloading recipes. Instead, it will include tips to help you ensure your shotgun shells fit in all your favorite shotguns, not just the one you shoot most of the time.

For those of you reloading enthusiasts who have a Spolar Gold or Ponsness/Warren or loader other than a MEC, this article will have little value to you except for general info on possible resizing problems. Your loaders insert shells into a full–length sizing die at the first stations, and the shell remains in that die until the shell is completely loaded. This article pertains to reloading machines with collet–type resizers, like the MEC.

The Whys & Hows Of Resizing

Recently I purchased a great little 28–gauge Remington 1100 Sporter. I intend to use it to teach my grandsons to shoot. The first thing I wanted to do was fire it to see how sweet it felt, but the challenge I ran into was not the gun fit or the fact it did not have a release trigger — the problem was my 28–gauge reloads would not fully chamber.

How many of you have dropped a reload into one of your autoloaders and attempted to close the bolt and it would not close all the way? If the shell is not resized properly, it will partially go into the chamber and stick when it gets to the part of the brass that exceeds the chamber size. To make the situation worse, when you push the carrier release, the shell will be propelled forward, wedging the brass in the chamber. As a result, it will be very difficult to get out. I would have preferred taking the barrel off and dislodging the shell from the chamber with a cleaning rod.

Resizing device

The MEC collet–style resizing device, when properly adjusted, can give you factory–spec reloads every time.

One of my other shooting friends suggested in the future, if I have a new autoloading gun I was unsure a reload would fit, I should take the barrel off and drop one of my reloads into the chamber by hand. That way, the bolt does not slam closed and jam an improperly sized shell in the chamber.

What surprised me was I had been shooting the same shells resized by my MEC 9000GN load in my K–80 and my companion’s Beretta 682, both with Briley tubes, for a long time without difficulty.

Let me digress for a moment. My MEC 9000 loaders have resizing collets on them, so I assumed the shells were being properly resized. But what had happened was, sometime in the past, the collet must have broken and I replaced it with a new one and failed to adjust the collet to resize the shell to the proper shell dimensions. The reason the resizing had not been an issue until this time was the shells I was reloading were being shot in the same two guns. As it turned out, the chambers in the 28–gauge tubes must have been very close to the same size. That was not the case with the new 28–gauge Remington 1100 Sporter. I am sure some of you who are more experienced reloaders are laughing at this point. How could I make such a beginner’s mistake…right?

Over lunch, I asked some of my gun club friends if they had experienced anything like this, and we got into a long discussion about resizing. I won’t go into all we discussed, but suffice it to say, everyone had an opinion. Some individuals indicated that, since they shot their shells in the same gun all the time, resizing was not all that critical, as the shells would actually fire–form in the chamber and should continue to fit in that particular gun without resizing. But shells with steel in place of the brass may be a whole different story. Others said you don’t want to “over” resize shells because you will cause brass fatigue. I understood the issue but had never experienced it.

It didn’t take a rocket scientist to realize my shells were not resizing enough to go into the autoloader’s chamber. The first thing I tried to do was resize the hulls by trial and error. I rotated the collar on the resizing collet, causing it to close more, and tried some shells. Unfortunately, I tightened up the collet too much, and it caused the primers not to seat fully. I am too much of a perfectionist to continue down that road, so I decided the best approach was to look into the ANSI/SAAMI specifications on shotgun shells, specifically the 28 gauge I was working on. (SAAMI stands for Sporting Arms and Ammunition Manufacturing Institute).

This very informative website has all the specifications for: centerfire pistol and revolvers, centerfire rifles, rimfire and shotguns. I was able to find detailed diagrams of all the various shotgun–shell dimensions and their respective chamber measurements.

To demonstrate visually what I had already experienced, I removed the barrel on the 28–gauge 1100 and tested one of my previously reloaded shells in the chamber. Well, duh, the sizing wasn’t even close!

Factory shell size

A factory Winchester AAHS 28–gauge shell with dial caliper. It measured .6200, and the adjusted MEC resizer on my 9000GN is now spitting out 28–gauge reloads measuring .6220, easily within SAAMI’s specs.

The SAAMI specs said the 28–gauge 2¾″ shell dimensions can be .6260–.0090 or down to .6170, and the chamber dimension is .6270. There was a note at the bottom of the page under the heading “chamber” that said “unless otherwise noted, all DIA +.005.″ I got my calipers out and measured several factory 28–gauge hulls just above the rim. The factory shells measured roughly .6210, well within SAAMI specs.

My once–fired, resized reloads measured .6330, which is larger than the .6270 size of a nominal chamber. When I compared the resized hulls to the chamber size, there was roughly a +.006 difference. You would not think that would be enough to make a difference, but it does. I adjusted the collet on my MEC 9000 to accomplish the correct resizing dimensions. Voila, problem solved.

If you don’t want to go to the trouble of reading the SAAMI specs or using a caliper to get the correct collet setting, MEC makes a great Shell Checker that sells for about $13. It basically gives you a Go/No Go test on hulls from a 10 gauge to .410 bore.

The terminology GO and NO GO is not like a rifle or pistol head–space gauge. According to MEC, you should resize hulls until they will slide into the appropriate GO hole and the shell slides down flush with the rim. They don’t recommend you resize shells down to the NO GO hole (–.002) because that can unnecessarily stress the resizing collet and could, over time, damage your reloading equipment.

One more tip: If you are shooting reloads in an autoloader or pump, it is a good idea to check the final crimp stage to assure the crimp is not bulged, making the diameter of the shell too large for the chamber.

During the initial crimp stage, a shell can bulge slightly at the end. SAAMI recommends adding a roll crimp at the final stage (for a 28 gauge, .613–.020). That roll adjustment can accomplish two things: It forces the bulged material toward the center of the hull to close any hole that might exist. It also makes the diameter of the end of the shell smaller than the chamber size (.6140+.005), which can significantly aid better chambering of the shell in a pump or autoloading shotgun.

I hope I have helped some of you avoid problems with resized shells. Resizing is sometimes necessary, but you must be careful to do it properly every time.

CAUTION: Read the notice and disclaimer on page 4 of this magazine. Always consult comprehensive reference manuals and bulletins for details of proper training, requirements, and procedures, techniques and safety precautions before attempting any similar activity.