TargetTalk

Greetings

I have an older Pardini sp22 - the model without recoil absorber (but with the raised stripes on the frame).

Recently, it has begun tumbling the bullets, making irregular holes in the targets at 15m.

Inspecting the barrel, there is a "bump", or ledge at the end of the chamber, where the rifling starts - on one side of the chamber. the other side of the chamber has a smooth transition between chamber and rifling.

What is the cause of this?, throat erosion? - can it be fixed, or do i need to replace the barrel?

Which brings me to my original question - how do i separate the barrel from the barrel weight? - we have a number of old target rifles in my club, so the plan is to make a new replacement barrel from one of these barrels.

doable or disastrous? - please advise! :-)

The Pardini barrel is press fit into the shroud. It will come out wiTh an arbor press. Making a Pardini barrel is not difficult if you use the old barrel as a template . Your barrel most likely has throat erosion.

A "bump" indicates the addition of material. Erosion is subtraction. I'm guessing you have a buildup of lead there, and a proper cleaning with a product like Shooters Choice will fix it. Tumbling seems more a problem at the muzzle than at the chamber. What ammo are you using? Have you recently switched? How frequently do you clean it, with what and from which end?

FWIW my first Pardini had mucho rounds through the tube with no loss in accuracy or other funny business. Infrequent cleaning with dry patches down the barrel - always breech to muzzle - and occasional wet cleaning of the chamber and extractor cut when they got too cruddy.

If you want a new barrel, don't fool around. Order one from Larry Carter and be done with it.

Greg Derr wrote:The Pardini barrel is press fit into the shroud. It will come out wiTh an arbor press. Making a Pardini barrel is not difficult if you use the old barrel as a template . Your barrel most likely has throat erosion.

Throat erosion in a .22lr? That would take millions of rounds to cause enough to make bullets tumble!

Making a new pistol barrel out of an old rifle barrel works quite well. I would make sure that you keep it the same direction as it was on the rifle and use the muzzle end if you can, providing it is of sufficient diameter. I have a barrel on my Free Pistol made from an old BSA smallbore rifle, it shoots very well.

I have a Benelli that will start to destabilize bullets after ~10 or 15 thousand rounds. I think it is due to lead building up in the corners of the rifling. When the holes get a little funny looking, I clean it using special chemically treated patch material that removes lead:

http://www.midwayusa.com/viewProduct/de ... ber=591584

That seems to fix it for another year or two. It's certainly cheap enough to try before you go the rebarreling route.

Throat erosion can be caused by a number of factors, round count is only one. How about material hardness? Also headspace? Even though a rimfire sears the round on the rim, too long a chamber will allow for early barrel wear at the point the bullet jumps from the chamber to the throat and rifling. That pistol could be 15 years old, with heavy use yes it could suffer from erosion. Bullet tumble can also be caused by a non concentric crown which creates uneven pressure on the base of the bullet as it leaves the barrel, creating yaw ( or tipping) I've bore scoped a few Pardini old barrels with erosion . If I can take a picture in the next few days I will try and post one.

As to getting a new Pardini barrel, some of the early designed barrels are no longer in production. In particular frames without a letter in the serial number.

I’d be surprised if throat erosion (which the problem probably isn’t, as William pointed out) would actually cause a .22 to tumble bullets. I’ve seen amazingly bad, deeply pitted and rusty barrels that are not accurate, but certainly don’t cause tumbling. I’d also say, check the muzzle end and clean the barrel and chamber well, using something that gets rid of lead deposits. When the buildup is thick enough, the edges of the rifling don’t necessarily grip the bullet and it may just push through. I’d guess leading that bad would be very obvious, though. Try a different ammo or a new batch of your old one.

Gwhite wrote:I have a Benelli that will start to destabilize bullets after ~10 or 15 thousand rounds. I think it is due to lead building up in the corners of the rifling. When the holes get a little funny looking, I clean it using special chemically treated patch material that removes lead:

http://www.midwayusa.com/viewProduct/de ... ber=591584

That seems to fix it for another year or two. It's certainly cheap enough to try before you go the rebarreling route.

That cloth is very effective at removing lead, because its mildly abrasive.
Bear that in mind when running it through your barrel

Its compound in it, I think similar to pumice, is harder than lead but a little softer than steel.

Old problem...easy solution.

Take an old .22 (or .17) bore brush and wrap a few strands cut from a copper "Chore Boy" around it. It'll rip that lead out in a few strokes with no harm to the bore.

You can get the "Chore Boy" at any super market.

Not so fast Rover- most Chore Boy now is copper coated steel. You need to verify the make up of the Chore Boy first.

Here are some images of a soft Pardini barrel I just got in for routine service. This belongs to a local club shooter who was not shooting a great deal. Look close at the breech face peening, and the hairline crack which has started at the extractor groove. The throat is also gone on the bottom, the area that gets the most exposure to powder burn.

As Greg has illustrated both verbally and optically, throat erosion in .22s happens. I once took a Winchester 52 that I considering buying, to Creighton Audette (rifle builder extraordinaire) in Springfield VT. Upon inspecting it for me, he noted a small crescent moon of throat erosion as shown in Greg's photo. He said that often times will appear around 20K rounds and will proceed around the circumference from there. As Greg noted, the ring appears on the bottom of the chamber first because some powder is pushed there with each shot fired, burns, creates a hotspot which causes the erosion over time.

Scott

Thank you all for the comments.

The pictures from Gregg are exactly how my barrel looks as well - maybe my barrel is a little worse.
My Pardini is pretty old - serial number B3xxx.
I have had it for 18 months, and have shot approx 4000 rounds through it.
I clean it every other month (always from chamber end), with a light oiling in between cleanings.
There is no visible damage to the barrel crown.
The tumbling is worse with "slippery" rounds like SK and RWS, than with Eley club and sport (wax).

Can the tumbling problem be caused by the throat erosion?