Fireforming 25-20 Brass in Marlin 27S

[25-20]

I have a nice little marlin pump 27S in one of my favorite cals 25-20, that I couldnt reuse brass twice , because of the chamber being oversize and splitting the brass (head separations ) Ive seen it mentioned that the oversize chamber was a common problem with this Model/Cal combo

So I necked up up the brass to .270 to create a false shoulder then used the 25-20 FlS die down only enough to allow a round to chamber. This was working nicely, held the brass back from flowing forward and making nice cases(bigger all around, but especially filled out with forward moved shoulder ) with no brass thinning for the first 10, until it didnt lock and blew open ,splintering the pump handle and gave me a facefull of powder, but luckily no real damage to me (glasses protected my eyes) . I had to slam it fairly hard to lock., so in hind sight, I should have brought the FLS die down about .010 more

Most guns have safety features to prevent firing when not locked, but I have had the same thing happen many years ago with a Stevens pump shotgun

My question is should the gun have fired when not locked/ Is there a safety feature that is not working?

[daville]

Sorry I cann't answer your question but I can cure your problem. I enjoy shooting my old Marlins as you do. I own a shop with in house gunsmiths. We could sleeve and rechamber the factory barrel and end your chamber problem plus gain a lot of accuracy. Cost is modest but is figured on the length of your barrel.

[25-20]

Hi I would like to go for a barrel reline and also for a Win 92 takedown in 25-20. But being in Canada it is difficult to send gun parts across the border. i have inquired about it here and no-one seems to reline in Canada.

Does anyone know what I should check and/or replace to get my Marlin 97S pump gun safety features working again, so it will NOT fire until locked? Also the Bolt release button does not work

Other wise the gun is in good shape and I can fireform brass to suit its sloppy chamber.

Thanks Phil