Minimum free pistol barrel length?

[boatschool02]

Former rifle shooter here. Used a 2013 with sight extension tube in college.
Recently switched over to FP and AP. Have Morini CM84e and Pardini K12. Loving it.
Plenty of benchrest discussion regarding optimum barrel length available online, but not much for pistols.

A couple of good groups on the FP target (only marginally bigger than my best with the Morini) with my friends Volquartsen 6" Scorpion have me wondering if anyone has experimented with incremental FP barrel length reduction? (I'm betting the AMU has.) Why not reduce the length, crown, and then add the full size comp similar to a rifle's bloop tube?

Is the factory Morini barrel/tube combo already harmonicaly optimized?
At what length will a Tenex lot tested Morini CM84e fail to hold the X-ring?
Has any one re-barreled with a different length, diameter, or contour?

Should be set up to test some of this in a few weeks, but thought I'd solicit ideas first. Would really like to see what the Eley club I have for practice will do.

Thanks,
Luke

[Rover]

As a former bench-rest rifle shooter, I find your questions interesting.

I'm afraid my answer will be disappointing. The FPs are so accurate that any improvement would be of little use compared to the inaccuracy of the users.

There are many threads on here on the relevance of pellet testing for improved accuracy. The bottom line is: It just doesn't matter.

[rmca]

All the more common free pistols (morini, toz, pardini, matchguns, hammerli, walther, etc.) can hold the x ring with no problems. Most will even hold the ten ring with cheap ammo.
Your Morini certainly can. So there's no point in messing with something that already works.

Two big differences in FP compared to rifle.
1- The ten ring is much larger
2- Your natural wobble won't permit you to do the groups you do in rifle.

So, even if your morini could do better with a shorter/longer barrel, you wouldn't be able to take advantage of it. And don't take this personally, almost none of us can! ;)

Hope this helps

[Tycho]

You want to play around, get a CM80 or 82 with the barrel tube - Cesare knew about harmonics 30 years ago...

[john bickar]

I think Daryl Szarenski and Chuck Gartland experimented with this a good bit.

However, there's the minor detail of learning how to hold a free pistol as steady as Daryl can, before this type of experimentation starts to bear fruit.

One needs to have a pretty steady hold to take advantage of a long sight radius. That has never been my strength.

[David M]

I made two barrels for the Morini prior to the Sydney Olympics. One was 14" and one 10" (standard barrel 12").
The 14" hand shot tighter groups with more in the Xring, but any trigger error was expensive, out in the 7-8 ring.
The 10" handled very well, not as many Xring 10's but it helped pull the errors in tighter.
The 10" really shined in the wind as very controllable and easier to shoot.
The 14" was then cut down to 10" and fitted to my wifes freepistol.
A later mod in 2004 was to put a rear sight extension to the pistol (similar to the short Airpistol), this gave me the same sight radius as the origional barrel but with the weight moved back into the hand.
Some time in the future I would like to try a carbon wrapped barrel to even further reduce the weight and move the CofG back again.

[Gwhite]

I'm unconvinced that barrel harmonics play much of a role with pistol length barrels. The short barrels would be mechanically stiffer, and the frequency of any vibrational modes much higher than in a rifle. The result would be much less deflection at the muzzle. Also, a pistol isn't held as firmly as a rifle, and that might tend to dampen any vibrations.

At one time, I think Anschutz made a smallbore rifle that had a relatively short rifled section, maybe as short as 10 or 12 inches. For legal reasons (at least in the US) you have to have at least a 16" barrel, so it was deeply counterbored. It was probably fitted with a bloop tube to get an even longer sight radius. The claim was that they found they could get better accuracy with the short rifled section. A short stiff barrel might be significantly less affected by minor ammo variations, which are always an issue with rimfire.

[boatschool02]

All,
Thanks for the comments.
To clarify, I'm not looking for additional accuracy. I would however like to test the difference between Tenex and Club for practice purposes. My pistol produces a 10 every time I do my part.
Rather I'm looking to apply a Pardini rapid fire mindset to FP.
If a pistol will hold deep Xs, why not make some minor accuracy sacrifices for "shoot-ability" if you can still keep it in the 10 ring or even the X?
I think the Pardini Bullseye SP and my buddies Volquartsen (plan to test soon) will hold the X ring with 1/3 to 1/2 as much time in the barrel and less weight out past the COG.
I agree regarding sight radius. Nothing more is required or desired at my skill level. I already shoot my FP with the extension tube flush and have been shooting my best AP X counts with the short Pardini and Steyr pistols.
My questions regarding harmonics applied mostly to whether or not anyone has tested the stock barrel with differently weighted comps/tubes or at considerably different lengths. If this combo or length/diameter ratio proves insensitive to minor changes, all the better.
Luke

[Tim S]

At one time, I think Anschutz made a smallbore rifle that had a relatively short rifled section, maybe as short as 10 or 12 inches. For legal reasons (at least in the US) you have to have at least a 16" barrel, so it was deeply counterbored. It was probably fitted with a bloop tube to get an even longer sight radius.

That was the original 2013, which had a 500mm/19.6in barrel; there was no counterbore, excepting the crown. It did have a 19cm extension tube, but this only brought the sight radius to the same as a standard Anschutz heavy barrel.

[ALBEITAR]

Take a look at this article in Rimfire Central:
http://www.rimfirecentral.com/forums/sh ... p?t=330394

[shaky hands]

I made two barrels for the Morini prior to the Sydney Olympics. One was 14" and one 10" (standard barrel 12").

So, which one did you use in the Olympics?

[zoned]

Take a look at this article in Rimfire Central:
http://www.rimfirecentral.com/forums/sh ... p?t=330394

Did the same to a FP60. 57mm were cut off the muzzle end, and the front sight assembly moved rearward. The result was balance resembling the earlier Hammerli 160 [sans weights]. In OEM mode the FP60 is like holding a pole.

OEM:


Bobbed:

[ronpistolero]

Beautiful work.
May I ask how the recoil is with the shorter and lighter front?
Also, have you vised the gun and to check on its new group? Would truly appreciate a picture of both the old and the new group it produces.
Thanks

Ron

[zoned]

....May I ask how the recoil is with the shorter and lighter front? Also, have you vised the gun and to check on its new group?

The recoil remains light and straight back into the arm. The mod just made the overall length of the FP60 about the same as the H160, so nothing unusual occurred in the firing behavior. With a FP recoil is not a concern, anyway, because it's a single-shot device. The bullet is through the paper before motion is felt and you aren't trying to align for a second shot.

The accuracy was not altered because the crown was properly cut, and there is still plenty of barrel length to stabilize the bullet. Same with the bobbed TOZ. Most standard match pistols these days only have 4" barrels and, at the league level, you can occasionally see a Pardini or Walther doing quite well at the FP game. What is more critical than barrel length is sight radius, but with the more nimble handling I find it much easier to hold a precise sight picture. Those rare individuals among us who actually have the skill to compete at the Olympic level would probably prefer the longest sight radius possible. For the rest of us mortals, we can still turn qualifying laps without needing a Formula 1 car. If you think you 'need' an F1 to do well, you're kidding yourself. The machine won't help you become a champ until you actually are one.

FYI, the FP60 is a very good platform for experimenting with barrel length. Beyond being a very durable and nice shooting pistol like its predecessor, its barrel is secured to the action with three setscrews. That allows it to be easily removed for chucking in a lathe. Same with the front sight block; two offset setscrews are used to secure and adjust its alignment. The later model Pardini K22 and current FPM also come apart easily.