Long vs. short barrel

[David M]

I have written this before in other posts, the difference between the long and short Morini is in its hold and shot character.
When shot on a scatt machine the long barrel morini gives me a hold pattern in a long lasy eight pattern across the ten/nine ring and shoots fairly evenly distributed shots. Good 10's, lots of very close 9.9/9.8's but very few if any 8's.
The shorter barrel still has the lasy eight pattern but the size is smaller and the frequency higher. It tends to pull the 9.9/9.8's into the ten ring but any poor trigger control it will push a poor 9 out into the 8 ring.
The net result is that the shorter lighter barrel pistol is not as forgiving as the longer barrel, on a good day it is worth 4-5 points more. But a bad day can cost you points.

[Shooting Kiwi]

FredB misses my point, probably because I made it so badly.

It has nothing to do with my personal preferences. I'm well aware of the physics. Yes, a high moment of inertia will be 'more forgiving', but, for the same reason, any swing that has developed (accepting that it's harder to start) is harder to stop (angular momentum is proportional to moment of inertia). Therefore, if you are having difficulty achieving a motionless hold, increasing the moment of inertia may not help, contrary to intuition.

Also, moment of inertia varies with the square of distance, but the torque required to hold up the muzzle varies linearly with distance. If pistol designers wish to maximise moment of inertia, whilst not requiring unreasonable effort to hold the muzzle up, a long tank (let's pretend it's a uniform rod or tube: moment of inertia of uniform rod = one third mass X length squared) may not be the best way to do it. A short, dumpy tank, with a light 'moment-of-inertia-controlling' weight as far from the grip as the regs allow might be better.

As for grip angle and bio-mechanics - probably justifies another thread. This one's rapidly going off-topic, for which I take some of the blame - apologies.

I suppose the question I should have asked is 'If nose-heaviness is so desirable, why don't we screw massive muzzle weights onto our standard pistols?'

[jipe]

Perhaps I should try again. We agree APs are nose-heavy, perhaps the most nose-heavy of any of the competition pistols. Why make them like that, and then compound the problem of the effort required to hold the muzzle up by making the wrist adopt a semi-drooped position, which is anatomically not particularly suited to the task?

Perhaps this was the reasoning behind some of the lod AP designs that had the vertical air/CO2 resevoir directly in front of the trigger guard....get less weight way out there in front, and get the center of gravity back closer to the hand?

Not weigth distribution was not the reason for the vertical reservoir. The reason was due to the working of the CO2 pistols: to work, the CO2 going into the pistol must be gaz, no liquid CO2 is allowed into the pistol. With an horizontal reservoir, when it is full (or when there is a little too much CO2 in it) there is a risk of having liquid CO2 into the pistol. This risk is eliminated with vertical reservoir.

This problem doesn't exist with air pistol, that's why air pistol with vertical reservoir never existed.

About the pellet velocity, all short barrel AP have a lower velocity than full size. There are two reasons for that:
- the baseline reason is that with the same amount of air, a short barrel has a lower velocity as the complete power of the compressed air (or CO2) is not used to push the pellet. Air rifle have an even higher velocity than pistols.
- to achieve the same velocity with a short barrel, more air would be needed, but the shorter cylinder contains less air than the full size cylinder, using more air/pellet would reduce the number of shots too much.

I have measured the velocity of the LP@ light of my wife and it is indeed factory adjusted at a lower value than my full size LP10 (also factory adjustment). With this factory adjustment, about 100 shots are possible per cylinders for the LP@ light, increasing the amount of air/pellet to increase the velocity would definitely bring the number of shots per cylinder fill too close to what is needed for an AP60 event where shooters typically shoot 70 to 80 shots, shighting shots included (remember than cylinder exchange on the range is not allowed, you need to move out of the shooting range).

For the grip angle, all modern standard pistols have a raked grip more or less similar to the rake of an AP. What I see is that shooters used to shoot big bore, 1911 types of pistols, usually like a more vertical grip, while shooters used to shoot AP and FP usually like a raked grip.

[Makris D. G.]

This problem doesn't exist with air pistol, that's why air pistol with vertical reservoir never existed.

There was in fact Walther LP201

[Packard]

Is the rifling the same for both lengths? That is, turns per inch? Will the added length further stablize the pellet due to added rifling?

Off a solid rest, is an air rifle more accurate than an air pistol (also off a solid rest)?

[jipe]

This problem doesn't exist with air pistol, that's why air pistol with vertical reservoir never existed.

There was in fact Walther LP201

Didn't knew that one, Walther made so many models of AP !

Originally, vertical reservoir came with the FWB C25, C55 and Walther CPM1. The LP201 looks like an air version of the CPM1 ?

[Tycho]

no, the 201 is a vertical tank - version of the LP200. interesting to shoot, btw, there is definitely something special about the balance. i think walther built it because the CPM1 was quite succesful.

[A74BEDLM]

If you leave the factory settings at default then Steyr claim upto 170 shots for a LP10 Compact and Walther claim upto 140 for the new LP400 Carbon Compact. Both of these are more then sufficient for a AP60 match. I assume that the factory setting velocity able to achieve the desired accuracy.