Crosman 140 design

[Jerry Cornelius]

I’ve recently resealed one of these and was struck what an elegant design the self resetting valve is

On the other hand, the fiddly loading arrangement and poor sights are a bit of an afterthought , and the trigger is only so so, so I don’t think it’s up there with the greatest crosman designs ever

The thing that really struck me was how inefficient pumping is. Obviously with these there is a concern about keeping the power under the limit so I put in a ludicrous 20 pumps to chrono it. Just under our limit. On the one hand phew, on the other wow that’s a lot of work for a result that a springer will give on one compression. 6 pumps, not a small number, gave only about 6ftlbs. It is very consistent though.

(Incidentally, in all the discussions I’ve seen about keeping the power down on these one thing I have never seen tried is using a smaller tp. I suspect that is what is keeping this one legal (hooray, though I’m also going to reduce the valve volume for added security). I may do some experiments.

[ratbuster2240]

They are well made guns JC. The sliding breech is a bit odd if you're use to a bolt, but I suppose they don't require cocking. I like the Elm stocks with the swirly grain but the blonde stocks (possibly Maple?) look nice too. The Crosman multi pumps always seem easier to pump in comparison to Benji/dan's.

[45flint]

I wonder if yours has been altered to assure legality in the UK. Mine pumps up quite quickly and though not as powerful as the Sheridan is close enough for my purposes. You are correct about the sight and loading cover. Crosman trying to keep costs down. They eventually upgraded with a bolt toward the end of the 1400 series. The internal engineering was always been some of the best. But I am always amazed that we Americans hold pumpers in such high regard? Good springer are just so much better, but you have to be willing to pay for it.

[45flint]

They are well made guns JC. The sliding breech is a bit odd if you're use to a bolt, but I suppose they don't require cocking. I like the Elm stocks with the swirly grain but the blonde stocks (possibly Maple?) look nice too. The Crosman multi pumps always seem easier to pump in comparison to Benji/dan's.

Crosman’s are easier to pump up as you say, the pump tube is not as big. Sheridan was going for power but at a price?

[Geezer]

I think something must have been done to restrict its power - a stock 140 should make at least 10 ft-lbs on 5/6 pumps.

[Jerry Cornelius]

I think something must have been done to restrict its power - a stock 140 should make at least 10 ft-lbs on 5/6 pumps.

Pretty sure it’s the tp. The original part has vanished to be replaced with a leather “washer”. For looks I will be replacing that with delrin and will experiment with different bore diameters to keep the power legal.

Otherwise everything seems stock, and the bolt seems airtight.

[trajectory]

I think a fixed length pump rod that keeps an air spce ahead of the piston in the closed position can be used to keep the power down as when set up properly, its very hard to explain fully, but the pumped air pressure cant go above a certain amount as the volume ahead of the piston becomes the limiting factor.

[deejayuu]

This is marked J C Higgins. Model 22 Sears & Roebuck USA Great fun and deadly accurate at 25/30 yds
https://imgur.com/XDXTZHh
https://imgur.com/izfJoTS
Any thoughts on value?

[smallholder1]

great little rifle all steel and wood no plastic sights are naff though I regret selling mine which on 6 pumps shot with good power

[Jerry Cornelius]

I think a fixed length pump rod that keeps an air spce ahead of the piston in the closed position can be used to keep the power down as when set up properly, its very hard to explain fully, but the pumped air pressure cant go above a certain amount as the volume ahead of the piston becomes the limiting factor.

Might that not lead to a dropping handle though? But it would keep the power down

People say it’s hard to keep the power under the limit but I’m not convinced. I do think it’s hard both to keep the power under the limit and keep the pumping efficient though, as my 20 pumps to get to 11.5 ftlbs showed.

[trajectory]

Might that not lead to a dropping handle though? But it would keep the power down

People say it’s hard to keep the power under the limit but I’m not convinced. I do think it’s hard both to keep the power under the limit and keep the pumping efficient though, as my 20 pumps to get to 11.5 ftlbs showed.

Guessing a drooping pump arm might be a possibility, not sure. Guess the pump arm linkage will still be in the same linear position regardless of the distance between the pump cup & the valve front, so maybe it will be ok or is there an over centre cramming action that wouldn't come into play with a 'short' piston rod?

[Jerry Cornelius]

In case anyone is interested in my experiments with TPs and keeping the power down:

L to r are the leather thing the rifle came with, (I am not responsible for that ) bit of air hose I had lying about with od 6 mm, id 4mm, fuel hose ditto od 6mm id 3.4mm, an aluminium tp I made from tube od6.3mm (6mm nominal), Id 2.9 mm (3mm nominal) and a brass tp made from rod od 6.4 mm (iirc 1/4” nominal) that I tried with bores of 2mm, 2.4 mm and 2.5 mm

All velocities are with 14.66 gn accupells

Both flexible hoses had essentially the same results, c 590 fts at 12 pumps and slightly hot at 20. Bother. This stuff was a doddle to work with too. Ho hum in the bin.

The alu tube gave 605-610 at 12 pumps, dodgy at best, and so unsurprisingly hot at 20. Bother again. Into the bin with it. Slightly hotter that the flexible tube in fact, which I am guessing was compressed between barrel and pump tube reducing its id

Ok, no short cuts, we are going to have to start small and work up. Brass at 2mm gave 380 at 12 pumps and 409 at 20. Taken out to 2.4 it was 490s and 540 respectively. 2.5mm gave 520s and 550s, which is to say 9 and 10 ftlbs. And there I left it because I couldn’t find a 2.6 mm drill bit and 10 ftlbs gives plenty of room for error anyway

So, restricting the tp is an effective way to keep these legal, albeit at the price of them being relatively underpowered (but fine for plinking) at a sensible number of pumps. My hunch, which I will test when I tidy my workshop up, is that a tp around 2.6-2.7 mm combined with sleeving down the internal volume of the valve is the easiest “no engineering “ route to legality without outrageous inefficiency (because you can keep the full swept volume of the pump)

Hope that may be of use to someone