I will say that a Match chamber is not necessary on a carry gun, possibly even a liability (in the practical, not legal sense.) I want my carry gun to have every chance of feeding the next round up and a "loose" chamber isn't going to hurt. I know it is the rage to fit all match everything for bragging rights, and I am as guilty as anyone :biglaugh: but braggin' ain't shootin'.

If your Para will group to your liking, and is reliable...it's o.k. with me if you use it

 

Welcome to the forum.

I think that your Para barrel is okay, I remember somewhere Glock chambers are .483? for .45ACP If someone can verify... I don't own any Glock 45s anymore.

Kuhnhausen says 1911 Chamber is .4812 as a reference, but I couldn't find the max dimension for you.

 

Should I be worried that the Para chamber is too loose,

I'd much prefer chamber dimensions to be .002" closer to max spec than min spec/too tight in a carry pistol.

The extra .0015" of 'slop' can allow a cartridge near marginal spec to still function in a dirty pistol, vice lock the pistol up solid from .01-.02"" of bullet setback.....

 

A fired case fits ONLY the chamber it was fired in. That is why they sell resizing dies and have new ammo for sale, it is made to fit any SAAMI chamber.

Try a new unfired case, if it fits, you have no problem, unless you want to reload w/o resizing.

 

A fired case fits ONLY the chamber it was fired in. .

I would venture to guess that fired cases from almost all Colt/Kimbers/Wilsons/Browns will then drop into my Glock 21's barrel with .002" of slop to spare...

 

Try a new unfired factory round- barrel out of the gun for safety

 

Factory Round

Factory rounds, as well as my reloads, are even looser in the Para chamber. Of course they drop into the Gold Cup no problem, but with little to no wiggle room.

I wish there were an easy way to actually measure the chamber dimensions. Headspace is OK and for a Commander sized barrel the gun functions and groups very well.

My concern is only that the chamber may not seal well at ignition and that gasses escape behind the case and/or the case slams hard against the breach. I have only put about 30 rounds through the gun so far but in those thirty no real signs of problems.

It just seemed odd that all other clearances and fit on the gun are nice and tight but that the chamber should be so noticeably different than a well-worn match chamber. I wonder if other P13 owners have experienced the same issue.

Thanks,
Jeff

 

You can make a casting of the chamber and then measure the casting to get an accurate measurement of the chamber. Brownell's sells cerrosafe specificly for the purpose of casting chambers.

 

Loose chamber?

I would call ParaOrdnance and discuss your concerns, as long as the gun is still factory and hasn't been worked on by a non Para gunsmith.

A loose chamber may not help accuracy, since the round my not center properly and consistently from shot to shot. The question is, does the gun shoot with good defensive combat accuracy? Personally, I like a gun to shoot as accurately as possible. However, I would think a gun that will shoot 3" groups at 15 yards, should be OK for defensive combat.

My personal self defense guns will shoot 2" five shot groups or less from 25 yards from a bench rest. My one exception is a Firestar in 9mm. The barrel length is under 4" and the sight radius is 4.75". The short sight radius makes it pretty tough to shoot groups, so I get about 3" groups at 25 yards with this gun, which is still OK for me.

 

It is more likely that your Gold Cup's chamber is undersize. They love to advertise "minimum match chambers" for target oriented guns and replacement barrels which are really undersize relative to SAAMI or Military Match standards.

 

That's what I was thinking (hoping). The nickel case in question was fired from the Para, not the Gold Cup. So it makes sense that it wouldn't chamber in the Gold Cup before resizing.

I'm going to put it back together and fire some factory rounds to see how it will group before I do anything drastic. And a cerrosafe casting sounds like a good plan, too, although I am fairly confident that the chamber is significantly bigger than the .4812 shown in the blueprints. Then the question will be how big is too big and how big would a replacement non-match barrel be anyway?

Jeff

 

SAAMI chamber diameter spec is .4796" -0, +.004" measured .200" in front of the breechface. So the book maximum is .4836". I doubt that even a little more would hurt.

Shoot the gun. I would rather have a sloppy chamber that worked than a tight one that did not.

 

Shoot the gun with factory ammo. If it is reliable and does not split cases then I would not worry about it. As someone else said a large chamber could be an advantage on a carry gun as it will help prevent jams.

 

As I said cast the chamber, then you know what you have. That way you will have some important measurements to relay to Para, so they can say one way or the other what needs to be done. I wouldn't do anything else for fear of voiding the warranty.

 

Update

:bawling:
Took it to the range today and resting my hand on the bench it wouldn't do any better than about a three inch group at 25 feet. Not very good considering how tight the bushing and rear lugs are, even considering my tired eyes and the plain three dot combat sights.

And the brass is very, very dirty on the outside; lots of gas getting by the outside of the case.

Bought the gun used, with almost no signs of wear elsewhere, sharp grooves in the bore. Doubt that Para will do anything about it as the second owner, so I'll be replacing the barrel. I'm really bummed as the fit, timing and lockup in the slide are all just about perfect.

Any suggestions on how to avoid getting another chamber this loose? Might consider a match barrel and then hone/polish it open a bit. Any favorite 3rd party brands among the Para owners? Remember it is a Commander length ramped barrel.

It did feed 225gr. JHP perfectly, and 185gr JSWC pretty well (2 FTF in 20 rounds).

Regards,
Jeff

 

I would try a few different kinds of FMJ ammo, and some cast bullets (and a few other known good shooters, no offense intended )before determining conclusively the pistol's chamber dimensions are the culprit.....

 

Agreed. Just because the it feels different/abnormal does not really mean anything.

Also, every .45 auto I've every picked brass up from, Glocks, 4500 Series Smiths, and 1911s, show a lot of soot/discoloration along one side of the case. Remember .45 ACP is a low pressure round and blow back of powder to some degree is normal.