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Joined: 01 Feb 2009 Posts: 64 Location: UK

For the last 10 years or so, I've been searching for a Win model 12 in 16ga - very rare in the UK. Finally, I've got one (1936, solid rib, polychoke, all original blue; a real beauty) and it's an absolute joy to use.

But...

It works just fine with (expensive and hard-to-find here in the UK) factory ammo, but it simply won't chamber reloaded shells. If I do force them in, either the breech won't lock, or else the action bar jumps out of the breech block. It's not the brass end of the shell that's the problem. It's the plastic.

I use Fiocchi and Cheddite hulls, which chamber with no trouble at all in my 16ga SXS. Makes no difference whether I use plastic (SP16) or fiber wads. I've been reloading for repeaters for 30 years and never had a problem like this before.

My guess is that the chamber tolerances on the Model 12 are just too damn fine, and you can't resize plastic like you can brass/steel.

Does anyone have any suggestions? If I have to use factory ammo, the model 12 will get used once a month, instead of twice a week like I've been hoping these last 10 years...

Any help gratefully received.

Member Joined: 02 Oct 2004 Posts: 425 Location: Maine

One of my 16g M12's will cycle reloaded Cheddites, most of the time, and one won't. Issue is they swell on firing, and the plastic drags on the chamber, causing the extractors to slip off. But the fact that your gun won't even go into battery suggests a resizing issue; I've always been able to close these guns on a bunged-up crimp shell. Cut the plastic off a fired hull, and see if the action will close on the metal head.

Guest

Hi Lemming,

Are you roll crimping or fold crimping.

When you fold crimp properly, the final crimp die will put a taper on the entire length of the reloaded hull, just like the taper in the chamber.

When roll crimping you expand the plastic when depriming(on most machines), but the hull never makes it back into the final crimp die, to be tapered. Then to make matters a bit worse, when you apply the roll crimp, it has the tendency to bulge the plastic a bit more, If the chamber is tight or dirty to begin with you will have the problem with chambering that you have encountered.

Just my experience.

Guest

Dogchaser is on the right track. Look at the mouth of a loaded shell, if it is belled out even slightly it will not allow the shell to chamber properly. Adjust you final crimp die to get rid of the bell and taper the hull.

Hello Lemming
A couple of questions,
Are you doing the reloading or another?
What machine is being used for the reloads?

Once you answer these, I think that we will be able to correct the issue

Mike

Joined: 01 Feb 2009 Posts: 64 Location: UK

Thanks to everybody for their replies.

Pumpgun -

Tried that; the metal head chambers just fine. It's the plastic that sticks.

Dogchaser -

I use a crimp closure. The chamber is clean and polished.

Skeettx -

I'm doing the loading. I use a Lee Loadall II and a MEC 600 Junior; at first I assumed it was the sloppy fit of the Lee and made up a test batch on the MEC. Exactly the same outcome.

The crimped head doesn't mushroom; it looks to have a nice rounded taper, and the crimp is firm and deep.

The test load I made up was;

616 primer
19.7 gr Unique
SP16 wad
30 grams no 7
Cheddite 67mm case.

This isn't a tight fit; you don't need to compress the wad at all, and there's the right amount of clearance between the top of the shot column and the base of the leaves. The case was once-fired ie not previously reloaded, and showed no sign of excess pressure.

Thanks again, gentlemen. I'd really appreciate it if we can find a solution!

Guest

I can undrstand why you might be having problems using the Lee, they are usually set up for 70 mm hulls.

Have you previously been loading 70mm hulls with the MEC?

Jest for grins would you run one of your loaded shells through your roll crimp tool and see if it will chamber properly in your Model 12.

Hello Lemming
I appreciate the answers.
I have three more and then we should be able to find success.

What hull length are you reloading? 2 3/4. 2 9/16 or 2 1/2 ??

Using a micrometer or dial indicator, please provide the average diameter of the heads, rims and mouth of the reloads.

Second, is there anyone near you with a 16 gauge chamber reamer>

Thanks
Mike

Guest

I don't think I explained it correctly.

If you can chamber a factory loaded round, there is no reason why you shouldn't be able to reload for this shotgun.

You are going to have to take some measurements of your reloaded rounds and compare them to the factory loaded rounds. Or compare them to actual minimum chamber dimensions. I will try to find them for you and post them.

Start just above the brass and work your way up measuring about every 6mm (1/4") approximately until you find out where the difference is. You cannot see the difference by eye you have to measure with a micrometer or a set of dial calipers.

I have a feeling that even though the fold crimp shoulder might be rounded, your final crimp die on the 600 jr, is not set properly. I wouldn't use the Lee machine until you find out what the actual final crimp die issue is. Also on the MEC 600 jr, if it has a plastic final crimp die, make sure that it is not cracked. I have seen a couple of the plastic final crimp dies crack, it isn't very common and it is tough to see on the black plastic die.

The chamber might be tight, but it has to be cut correctly or the factory rounds wouldn't fit.

Guest

Minimum chamber dimensions for 16 gauge, 70mm hull are.

Breech end is .7458 inch
At the forcing cone is .732 inch

The included taper of the chamber is .005 inch per inch (all gauges have the same taper)

These are MINIMUM dimensions. I wish I could find the actual dimensions for the ammo.

The absolute largest crimp end of my reloaded hulls on a Mec Sizemaster is .728, taken at the very end of the hull with the caliper anvels flush with the top of the hull. The Remington hulls had the largest dia. at .728 the Cheddites I reloaded were the smallest dia. at .712.

I hope this helps.

Member Joined: 02 Oct 2007 Posts: 1975

I measured 6 of my federal reloads and they averaged less then .720 at the fold crimp end. My 2 1/2" roll crimps measure .728. Heres some charts showing the chamber measurements.

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Click on the pictures and they'll come up full size.

Guest

Hi spr310,

Where did you find those drawings for cartridge and chamber?

I was trying to find those for this fellow, I could only find my chamber drawings.

Member Joined: 02 Oct 2007 Posts: 1975

Dogchaser. The charts are in A Shotgun Gunsmithing book by Ralph Walker that I bought back in the 70's. The book has quite a bit of information in it.

Joined: 01 Feb 2009 Posts: 64 Location: UK

Twicebarrel -

There aren't any 70mm hulls in the UK... we only have 65 or 67mm in the UK. The MEC is set up for 67mm.

I tried running a crimped shell through the roll turnover machine. It still won't chamber!

Skeettx -

measurements as follows;

rim 0.827"
brass head 0.741"
plastic case 0.729"
head 0.728"

I have adjustable reamers that'd make that size, but there's an additional problem. Under the draconian UK gun laws, repeating shotguns have to be permanently modified to take no more than 2 shells in the magazine. This means crimping the tube and permanently fixing (welding) it to the receiver. With a Model 12 this means the block into which the barrel and mag tube fit has had to be welded to the receiver; so the barrel can't be removed. Ever. Just be grateful you live in a civilised country.

Accordingly, reaming the chamber isn't an option