Mechanics of Shotguns


September 15, 2008, 10:02 PM
Forgive my ignorance, but in the field of pump shotguns, how distinctly different are the actions?

I know that the Rem 870 has a single bar inside (whatever you call the part....sheesh) and Mossberg has a double bar.

What's inside the Benelli's and others? Are any of the mechanisms truly unique, or finely engineered? Are there any smooth, like a watch mechanism?

One of the gunsmith students I spoke to recently, discovered that one manufactuer has been producing the same mechanism for 40 odd years, even though it could easily have been improved upon. They don't, because why change it? It isn't broke. So goes manufacturing.

Educate me.


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September 15, 2008, 10:22 PM
The only ones I'm really familiar with are:

browning auto5
winchester model 12
montgomery wards model 35
ithaca bottom eject
winchester model 97

These shotguns are totally two on that list are anything like eachother. BTW, from that list, my favorite by far is the montgomery wards model 35

Jeff F
September 15, 2008, 10:23 PM
870 with single bar slide is news to me. I have an 870 in my hands right now and it has two. You might be thinking of the extractors, the 870 has one and I think the Mossberg may have two. I don't own any Mossberg's.

September 15, 2008, 10:41 PM
I think he has them swapped. the Mossberg has one bar connecting the pump to the action if I remember right.

September 15, 2008, 10:46 PM
The Remington 870 has two bars (action bars) and I am not sure about the Mossberg. The secrete to any good reliable mechanism will follow the KISS principle, so why change it.

Shotguns are like fine spirits or wine, the smooth and mellow with use.

September 15, 2008, 11:16 PM
870 - 2
500 - 2
M37 - 1
1897 - 1
BPS - I forget
M31 - Dunno

September 15, 2008, 11:28 PM
bps has 2 bars. Very smooth action.

Dave McCracken
September 16, 2008, 07:52 AM
There's some variance, but out of the box the two smoothest actions are the Remington 31 and the Winchester 12.

Ithaca's 37 is also smooth but not quite as good.

870s, bless them, and others need a little work polishing to smooth up. Mine are getting there.....

September 16, 2008, 08:53 AM
Earlier Mossberg 500's and Maverick 88's have a single "Slide Action Bar" {or whatever it is called}...the bar that connects the pump handle/ forend to the bolt & bolt carrier assembly.

Newer 500's and Maverick 88's have 2, just like the Rem 870.

My 1990 vintage Maaverick 88, and OLD Mossy 500 both have 1 slide action bar.

September 16, 2008, 01:03 PM
Out of what I own, the slickest new out of the box for me would be the BPS. Otherwise a 1300 I have will open the action itself when standing in the corner buttstock down. It ain't worn out. Just slicked up from a lot of use.

September 16, 2008, 04:42 PM
The new Mavericks 88s have 2 also.

September 16, 2008, 04:53 PM
Improvement is often times in the eye of the beholder. Remington has had the same design for 60 years and there is absolutely nothing wrong with it in my opinion.
There are distinct differences in design between most guns, but the most obvious differences are between the open bottom, bottom ejecting mechanisms, like the Ithaca 37 and the Browning BPS, and the side ejectors like the Remington, Winchester Model 12, etc. Remington has made left handed versions, but the bottom ejectors are ambidexterious to begin with. The way they function is very different. You need to watch one to understand.
A pump gun is about the most reliable gun you can get, and one from any of the major manufacturers should serve ione well. They do feel different. I like the feel of the Remington.:)

September 16, 2008, 05:23 PM
The fastest pump guns are the ones that won't accept shells longer than 2-3/4". Apparently, in the old days they actually had shells shorter than that and there were some guns that wouldn't chamber the "long" 2-3/4" shells. Those may be the fastest pump guns of all. I've never shot them so I don't know. For me, the grip style also makes a difference, as well as the weight distribution(or balance) of the shotgun. The size of the fore stock seems to effect my speed too. How slick the action is doesn't seem to have any effect at all on my speed. Although I've never shot a shotgun that wasn't at least average slickness or better. So I might change my mind. I've never owned a brand new shotgun either.

In the days before they actually started to put actual pistol grips(like an AR rifle) on shotguns, the grip styles were categorized as: 1. straight 2. semi pistol, and 3. pistol

This is a straight grip:

This is a semi-pistol grip:

pistol grip:

I can't stand pistol grips. They slow me down somehow. semi pistol grips seem to be the fastest for me. The double barrel guys claim a straight grip is the fastest. It probably is for a double barrel, but when you have to pump the shotgun, you need a little bit of curvature to speed the pumping action, imo.

The monkey wards model 35 seems to be the best overall combination of everything...balance, grip shape, forestock size, trigger size and shape, yada yada. The loading gate is a little funky though.

Hollywood Marine
September 20, 2008, 02:26 AM
IMHO, the winchester model 1912 is arguably the smoothest pump shotgun ever made. When I put a snapcap in my trap m-12, stand it on the recoil pad and pull the trigger it falls open until stopped by the hammer. I once told our moderator, after shooting his 870, that it was like shooting a model 12 that was full of sand.

Dave McCracken
September 20, 2008, 08:59 AM
And yet we're still friends....

September 20, 2008, 10:42 AM
With forged and machined steel parts, the ultimate reason for discontinuation in 1963 was that it was too expensive to produce at a competitive price. The primary competition at this time came from the much less expensive Remington Model 870, which had been introduced in 1950.---from Wikipedia

Okay, now we're getting somewhere.

I can only wonder what the going price for one would be, which Wikipedia indicates was offered till 2006 in several Collector's Editions.

I'll bet I couldn't touch one now for under $1,000.00, right?:):)

Fred Fuller
September 20, 2008, 04:53 PM
One what? Model 12?

Around here good used ones in field grades go for $350-$500 depending on condition and original trim level, some fancier ones are more. Don't know the price range in your AO.

A Model 12 that has been shot A LOT will batter the locking recess cut into the top of the receiver for the back of the tilting bolt to lock into and get loose as far as headspace is concerned. The fix last I knew is to have it welded up and recut, not an inexpensive proposition. Not often encountered, but something to be alert for in a heavily used Model 12.

Another thing to keep in mind is that Model 12s don't have disconnectors. Pump it briskly with shells in the magazine and the trigger not released and it will fire again as soon as the bolt closes. This can be an unpleasant surprise for shooters unaware of this design detail, as well as for those around him when he discovers it. Same thing goes for older Ithaca 37s and a couple of other older designs, like the Winchester Model 97, the Savage 520/620 etc.

The shotgun matters less than the shooter... get good enough for the gun not to be an issue. 8^)


September 20, 2008, 05:09 PM
Most of the differences these days are ergo more than function.

September 20, 2008, 06:10 PM
Thanks Lee, that's a good cautionary comment.

I'll check out some stores and see what the price range is on those.

September 20, 2008, 11:02 PM
IIRC the first Model 12 was a 20 gauge gun introduced in 1912. The 12 gauge was introduced in 1914.

It was made until 1980. The gun changed in 1964. Before the change it would fire if a round was chambered while holding the trigger. After the change it was introduced as the "Y" model which required that you release and pull the trigger after chambering a live round to make it fire.

A "Y" model has a Y at the beginning of the serial number.

I've seen several dozen Model 12's purchased by fellow Trap shooters at my club. They paid between $600 and $1,400 for vented rib Trap grades. For the most part, condition of the gun, accessories (extra barrels) and wood determine the value.

I am considering buying one from a fellow Trap shooter. He wants $1,000 for his gun with a Monte Carlo stock and a donut posted rib.

Model 12's used to be THE gun for both Skeet and Trap. People don't use them in competition much anymore in either sport (Trap shooters do more than Skeet shooters).

28 gauge Model 12 are getting to be rare. You've made a deal if you can get a 28 gauge in good condition (80% or better) for under $2,500.

I personally thing they are a great shotgun.

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