Page 1 of 1

A peculiarly British Model 37 problem

PostPosted: Mon Mar 05, 2018 7:48 pm
by impala59
Gentlemen,
As some of you may know, we in the UK have a 2 tier licencing system for shotguns, up to 3 rounds capacity is a "shotgun", over 3 rounds is a "firearm" I know, seems a bit crazy, but there it is, we live with it. Most of my collection of 37's and other pumps are in the former category simply because it is much easier to own them and for game and clay shooting 3 rounds is plenty, indeed, many of you over the pond are limited with your duck plugs, so not so different I guess.
In order to be rated as a "shotgun" a pump (or semi auto) is modified in the following manner; Firstly the magazine tube is crimped around its circumference at a point that will only allow 2 shells in the tube.(+ 1 in the chamber makes the max capacity 3) The magazine tube is then permanently attached to the receiver by welding, brazing or permanent thread lock. The gun is then examined by the official proof house and then stamped with a proof mark.
So, to my problem. One of my old 37's suffered an odd fail on the clay range. After a few rounds the magazine spring appeared in the load/ejection port as the follower had suffered a complete fracture failure. It was a metal, hollow follower and the 'disc' part detached from the 'tubular' part which remained in the gun. The problem, of course is that I cannot replace the follower as the remaining part is captive within the magazine tube between the receiver and the crimp. I actually have a spare modern nylon follower but I can neither get that in or the damaged part out.
With the magazine spring removed, the old follower still slides back and forth and stops correctly at the receiver end.
Any Ideas Gentlemen?
My first thought is to glue a piece of wooden dowel within the old follower for the spring to bear upon, but I would appreciate your input

Re: A peculiarly British Model 37 problem

PostPosted: Tue Mar 06, 2018 5:10 pm
by 1977cutcher
Well, first off if you get the old follower out is there enough give in the new one to get it back in past the crimp? If so I would keep working on the follower to get it out. Perhaps tapping on the edge with a long dowel to get it started into the receiver followed by some careful prying with a screw driver? What vintage is the model 37? Does the magazine tube have the taper or crimp to hold the follower in place near the receiver?

Re: A peculiarly British Model 37 problem

PostPosted: Tue Mar 06, 2018 7:07 pm
by impala59
Hi, and thanks for responding
I believe that it has the crimp at the receiver end, hence the metal follower which may well negate using the later nylon follower which I believe works with the taper. I shall dig it out of the safe tomorrow and have a thorough check and maybe some photos. I will get back with more info, thanks again

Re: A peculiarly British Model 37 problem

PostPosted: Tue Mar 06, 2018 7:43 pm
by twistedoak
the more worrisome part of this whole thing is
can you get a new one in ?

getting the old one out is easy as collapsing a side
the metal as you see, isn't the thickest
and now that its a sleeve it should give easily
like a tin can without the rings on the top or bottom

i'm not sure if you can get a nylon follower past the crimp
maybe it will give enough to pop past
if it was a metal follower i'd suggest disassembling the gun and heating the receiver and mag tube in an oven
then i'd put the metal follower in dry ice

Re: A peculiarly British Model 37 problem

PostPosted: Wed Mar 07, 2018 5:08 am
by impala59
twistedoak wrote:the more worrisome part of this whole thing is
can you get a new one in ?

getting the old one out is easy


I agree! I guess using heat would free up the thread so that I could unscrew the mag tube, but, technically I would then be in breech of the licencing laws as it fundamentally states " non removable magazine" This, I guess, is to prevent us from simply buying a new mag tube to increase the capacity.
The photos show the stop ridge and possibly the taper, also the "legal" tube crimp
6537foll (2).JPG
6537foll (2).JPG (90.04 KiB) Viewed 2631 times
6537foll (4).JPG
6537foll (4).JPG (86.28 KiB) Viewed 2631 times


While I had it apart this morning, I decided to attempt a "field fix" I cut a 1" length of 12mm nylon and some 1" lengths of plastic tube that I had around. I split the tubes and added to the nylon rod until I had an "interference" fit on another metal follower from another gun. I then pushed this into the broken follower from the muzzle end with a rod and added a touch of glue. Pretty it ain't! But it seems to work. The new 'plug' is a tight fit in the follower and the follower moves freely. I will build up a 'button' with Loctite 3090 to make it cosmetically more appealing. In the long run, I guess that I will get a gunsmith (who can legally remove the tube) to heat and remove it to replace the follower. This 1965 gun needs a re-finish anyway and any damage caused by heat needs to be done before I re-blue.
Meantime, I can still use this old favourite. Funny how despite having many 37's and other pumps, one old clunker can remain a favourite!
6537foll (7).JPG
6537foll (7).JPG (197.43 KiB) Viewed 2631 times

Re: A peculiarly British Model 37 problem

PostPosted: Wed Mar 07, 2018 11:13 pm
by twistedoak
well I wasn't referring to removing the mag tube with heat .
the idea is to heat and expand everything
this will give you a few thousandths more room to slip a new follower past.
if you freeze a metal follower it will shrink it a few thousandths
thousandths add up
i'm guessing they did a through job in creasing to limit shell capacity ,the factory stop crease could be more forgiving

its an old trick for installing close fitting components like bearings
you'd be surprised at how much you can get something to expand or contract with heat and cold

Re: A peculiarly British Model 37 problem

PostPosted: Thu Mar 08, 2018 6:50 am
by impala59
Now that’s why I love this site! Such lateral thinking and old engineering tricks that you won’t find elsewhere! I shall do some measuring to see what the differences in size are then maybe have a go. Thank you Sir!

Re: A peculiarly British Model 37 problem

PostPosted: Tue Mar 20, 2018 2:48 pm
by 1977cutcher
Just curious as to how you made out on this problem?

Re: A peculiarly British Model 37 problem

PostPosted: Fri Mar 23, 2018 6:59 am
by impala59
I decided to have a go at the heat/freeze method through the receiver end but as insurance I did not destroy the original follower in case of problems. I removed my temporary plastic plug and wired the original follower to the muzzle end(the crimp) with the view that if successful I would simply crush it and remove through the crimp. With the gun stripped down to just receiver and mag tube I heated it whilst freezing both a metal follower and a nylon one. Unfortunately, I could get neither past the step and decided to forego any forcing that may create other problems. After the application of heat I also tried to unscrew the tube, again to no avail.
I have now returned to my ‘field fix’ I have carefully dremelled the rough edges where the follower separated and have glued in the plug with a plastic finishing cap which looks ok cosmetically. It works fine and I can live with it.
Before cleaning up the old follower, I inspected it with a magnifying glass to try and see what caused the failure. It looks as though at some time in the guns life it had been put away with water within the cup, stood muzzle up for a long time it seems as though the water just ate through the metal. This gun was in a fairly bad way when I got it and a component level take down did in fact reveal rust internally as well as externally. The one part that, due to the magazine restriction that I could not remove and check was the follower. I wonder if the hollow cup is one reason for the change to a nylon part?

Re: A peculiarly British Model 37 problem

PostPosted: Fri Mar 23, 2018 4:34 pm
by 1977cutcher
Well, it's to bad that the fix didn't pan out. As far as the nylon material I believe it was a combination of cost saving as well as a bright indicator to show that the magazine is unloaded.

Re: A peculiarly British Model 37 problem

PostPosted: Fri Mar 23, 2018 5:54 pm
by twistedoak
how hot did you get it ?
you let it heat soak for awhile before trying?i'd bake it for 2-3 hrs at least
while I would try baking something else first to see the effect it has on the blueing ,,
500-600-700 degress F ,will not damage the metal structure.

and dry ice will shrink the metal considerably more then a freezer will..

Re: A peculiarly British Model 37 problem

PostPosted: Fri Mar 23, 2018 7:44 pm
by impala59
I guess that I was maybe a bit over cautious, I had the receiver in the oven on max for a good couple of hours, the followers were in deep freeze overnight as I had no access to dry ice. A bit scary I suppose (but not as scary as my wifes questioning look at what I was cooking!

Re: A peculiarly British Model 37 problem

PostPosted: Sun Apr 01, 2018 8:17 am
by twistedoak
ok
depending on how aggressive you want to get in fixing it ...
I mean it may be cheaper to get a legal gunsmith to just do it.

but
you could also try to locate a tube expander in the appropriate size.
slide the expander down the mag tube and expand the crease just enough to get the follower past
you could then recrease it ,or not afterwards.

expanders aren't found in corner hardware stores ,
but there is a surprising amount of sizing and designs out there used in industry.
tell the retailer your measurements and intended usage and they probably have one

Re: A peculiarly British Model 37 problem

PostPosted: Sun Apr 08, 2018 3:54 pm
by impala59
Hi and thank you for your interest and advice!
I had another go at the heat and cold but no real joy there. I do have a friend with an engineering workshop who is likely to have an expander, probably got the rounded rotary device to re-crimp too. Another friend of mine who I was talking to at the shoot today, reckons that the best way would be an M19 socket with a length of 10 mm studding bolted to it, hammered through the constriction, reverse hammered on the other end of the studding(having attached a piece of scrap to it) to remove and make a second pass. This, he assures me, will free the follower. Then refit the new follower, test and re-crimp with a dulled tube cutter. He is a registered firearms dealer so can do it in his premises quite legally. Sounds quite violent but he is confident and has done similar before apparently. I will let you know the outcome

Re: A peculiarly British Model 37 problem

PostPosted: Mon Apr 09, 2018 4:14 pm
by 1977cutcher
Hope it works out!

Re: A peculiarly British Model 37 problem

PostPosted: Mon Apr 09, 2018 7:01 pm
by twistedoak
I personally wouldn't hammer it.
a tube expander is a a round metal body with 3-4 rollers in it
a mandrel is inserted into the center and it is turned
as it feeds down tru the expander the rollers flair out

Image
rough example ,a different design would be needed

Re: A peculiarly British Model 37 problem

PostPosted: Tue Apr 10, 2018 7:55 am
by impala59
I'm with you on that!
I shall visit my engineering friend soon and see what we can accomplish
Once again I thank you for your interest and advice

Re: A peculiarly British Model 37 problem

PostPosted: Sun Sep 23, 2018 11:01 am
by impala59
To finally conclude this post, I have at last made the repair, following the good advice given and with a little invention (in England we call it bodging!) :D
Firstly as suggested I removed my temporary repair and carefully got down the side of the damaged follower and then crushed it inwards to facilitate removal. I was offered a hammer type mandrel but elected not to use it. (It was a Brownells mag tube dent remover).
My engineer friend was busy tied up with other projects so I sat down and thought about what I needed to do. I found in my garage a 12mm (thread) expanding bolt fixture, the outer diameter was 20mm and it expanded to 24mm. I fitted a length of 12mm stud, a 20mm tube spacer and a couple of nyloc nuts to rotate with. Setting the depth outside the tube and marking with electrical tape I proceeded to gradually expand the crimped area until I could push a new nylon follower through. Finally, using a blunted tube cutter I gently re-established the required legal crimp to ensure 3 round capacity

37 follext (2).JPG
Home-made tube expander
37 follext (2).JPG (62.38 KiB) Viewed 361 times

37 follext (1).JPG
The new follower in place
37 follext (1).JPG (78.92 KiB) Viewed 361 times

Re: A peculiarly British Model 37 problem

PostPosted: Sun Sep 23, 2018 3:09 pm
by 1977cutcher
Well done.

Re: A peculiarly British Model 37 problem

PostPosted: Tue Sep 25, 2018 11:28 am
by twistedoak
:D
i'm glad it worked out
and better yet when you can use household items