Reaming a 22LR chamber? How

[dwebb210]

I've got a Sig Trailside .22 pistol.

It is a target grade gun, that prefers target grade ammo.

Unfortunately, I bought it for plinking.
And I prefer the cheap Winchester Wildcat ammo.

Most bullets will drop right into the chamber until the rim meets the breach. These load and cycle just fine.

When I got the gun, about 10% will not freely drop in as far.

This is a known issue with this gun. I looked into it
when I first got the pistol a couple years ago. It seems
that my gun is too snobbish, and hates imperfect ammo.

When this happens, the slide doesn't completely reach the
breach, and when the trigger is pulled, the hammer's inertia
spends most of it's energy pushing the slide the rest of
the way closed, and I get very light primer strikes.

I found a drill bit that was smaller in diameter than the
chamber, but larger in diameter than the barrel.
I chucked the bit into a drill backwards, and inserted the
shank into the chamber with a dab of lapping compound.

This helped a lot, but about 5% or so still get light
primer strikes.

I think I'm on the right track, and my gut says I need to
buy a real reamer for this job to do it right.

I'm pretty sure it is the lead bullet not being perfect
on every round that is causing the hangups. There is
quite a bit of variation between bullets, and they are
all a little out of round. (when measured with micrometers)

I'm thinking I should just extend the length of the chamber
a 16th of an inch.

Anyone done this before?
What size reamer is needed?

The only gunsmith in the area is months behind on his work,
and this seems like something I could do myself.

Any help/advice would be appreciated.

Thanks!

Dave

[tous]

Failure of the cartridge to completely enter the chamber is likely a diameter, not a length problem. Reaming a chamber is not a do-it-yourself project unless you have a lathe and the proper fixtures to center the part. Using the back end of a drill bit and a hand drill will probably damage the chamber.

If you must lap the chamber, use a brass mandrel with a fixture that keeps it centered. A fired .22 LR cartridge will work, but I urge you to re-assess your planned solution.

Find a catridge that sticks in the chamber. Color the case with Dykem Blue or a Magic Marker. Re-insert cartridge until it sticks, then rotate and remove. Where the color wears off is where the problem is.

We need to consider, is damaging a $200 barrel a better approach than buying ammunition that feeds well?

Good luck, mi amigo. <c>b

[Allman]

I'm assuming you think the chamber is too tight and want to enlarge it for a bit looser fit?

First, do a chamber cast on the chamber. Then go to Midway's site and search for 22 reamers. Look up each reamer and go to the technical specs page. You will find the dimensions of each reamer (size chamber they cut). Some 22lr chamber reamers cut larger than others, have different tapers, throats, etc. Buy the one you think will solve your problem (comparing it's dimensions against the chamber casting you made) and recut the current chamber with it. If you don't know how to cut a chamber you should have someone who does either do it or show you how to do it.

A quick note on chambering (assuming you have the basic idea) for your first chambering job: Go SLOWLY. Cut a few thousandths at a time removing the reamer, cleaning it and the chamber thouroughly, and relubing it between cuts. Turn the reamer slowly by hand, do not use a drill, lathe, or something (the chamber is already cut and you will be removing only a tiny bit of metal when cutting it to a larger dimension). Be very carefull to feed it straight into the bore axis so you don't oval the chamber. Do NOT turn the reamer backwards, it will dull it instantly and make it usless till resharpened. Use a good quality lube for reaming, tapping or raming fluid made for steel, and keep the reamer well lubed and completely free of any shavings, When removing the reamer between cuts, try not to rotate it at all till it is out of the chamber, to avoid a chip getting caught betewwn the reamer and chamber and scarring it. The reaming will probably go much faster than you are anticipating, so be carefull and DO NOT go too far. After the reaming is complete, try polishing the insides of the chamber walls with a tiny felt pad (just large enough for a semi tight fit in the chamber) and some fine polishing compound to remove any scratches. Keep in mind at all times that it is easier to remove metal than to put it back.

Chamber reamers for .22's cost around 40 bucks and can be resold on ebay for near, sometimes more, than you pay for it if you don't ding it up. You may want to check the cost of a new barrel and keep that in mind before you start. It's not all that difficult, but first time attempts at any gunsmithing are frequently best made on cheap parts just in case. (BTW, don't get that drill bit, either forwards or backwards, anywhere near a barrel again. Sounds like you got lucky this time, use a felt pad in the future and spend the extra time. Steel against steel, with or without lapping compound, is far too agressive for a chamber polish)

[ToddCrow]

Brownells sells chamber reamers that be used by hand, they have a long mandrel that fits in the bore keeping the reamer centered.

There are alot of different 22's reamers, they make different ones for match guns, bolt guns, semi-autos, etc., so make sure you buy the right one, best to call them.

Use lots of oil and go slow.

[fastvfr]

Of course, you know that the lovely Sig semi-match chamber, which once could have brought you excellent accuracy, will be destroyed in this process if it hasn't been already, correct?

And then you have to face the possibility that the bolt/extractor may need to be tuned to deal with the unanticipated slop of the now-looser chamber...

In your position, the first thing I'd do is buy a new barrel for it from the factory. Chances are you could have had Sig do the work, BTW...what if that chamber was cut with an undersize reamer? They could have done it right for the price of shipping.

Anyhow, once you have an unaltered factory barrel again you can just drill out the mess you have made there and sweat a pre-chambered liner into that barrel.

Have you shot the thing for groups after your first attempt at hoggin' out the chamber? Are the cases bulging/cracking at all or harder to extract?

Good luck, man.

[dwebb210]

Originally posted by fastvfr
Of course, you know that the lovely Sig semi-match chamber, which once could have brought you excellent accuracy, will be destroyed in this process if it hasn't been already, correct?

And then you have to face the possibility that the bolt/extractor may need to be tuned to deal with the unanticipated slop of the now-looser chamber...

In your position, the first thing I'd do is buy a new barrel for it from the factory. Chances are you could have had Sig do the work, BTW...what if that chamber was cut with an undersize reamer? They could have done it right for the price of shipping.

Anyhow, once you have an unaltered factory barrel again you can just drill out the mess you have made there and sweat a pre-chambered liner into that barrel.

Have you shot the thing for groups after your first attempt at hoggin' out the chamber? Are the cases bulging/cracking at all or harder to extract?

Good luck, man.

As far as I can tell, it shoots as accurate as it ever did.
If I loose 1 moa with a 22 pistol, I won't loose any sleep
over it. It isn't as if we are resting it on sandbags
for anything other than resighting the scope.

Extraction isn't any more difficult. I don't believe
I increased the diameter of the chamber. I was only
attempting to lengthen it a hair.

Everyone I have talked to that owns these guns have had
the same problems when shooting ammo that is less than
match grade. So I don't think it was made incorrectly.

The problem with these guns is that the barrel and frame
are one piece of metal. You can't simply change the barrel
like you could with a Ruger Mark II. And yes, I tought
long and hard about what I was doing before my first
attempt at surgery.

[agalb]

I believe this is the first post I have ever read about someone wanting to make their gun LESS accurate. I am speechless......

[dwebb210]

Originally posted by agalb
I believe this is the first post I have ever read about someone wanting to make their gun LESS accurate. I am speechless......

At this point, I'll give a little accuracy if I can gain
reliability. Whats the point in having an autoloader that
won't.

[agalb]

Trade your Sig for a Ruger. Don't mess up the Sig.

[dwebb210]

Originally posted by agalb
Trade your Sig for a Ruger. Don't mess up the Sig.

I came here looking for advice.

The best advice was to have a gunsmith do the work.

That is what I'm looking into now.

I considered a Ruger, but I liked the Sig better.

[fastvfr]

Good deal, D!

Hope that works out for you--at least if it goes to crap you have someone else to blame, right? That's always important. ;f ;a ;f

[hsvhobbit]

I'm not sure I totally agree with everyone here. You have a problem with the gun performing as you desire it to. You want to fix that problem. That's your choice.

Three easy ways to do it as I see it.

1) buy a reamer, follow Allman's post VERY closely and go for it...Don't skip any steps though and GO SLOW...Litteraly a few thousanth's will make a large difference

2) find a good gunsmith and let him do it...this route takes the worry off your shoulders assuming you find a GOOD gunsmith who's done this kind of thing before

3) send it to Sig and let them do the work...this is the route that I'd take personally. Buying the proper tools is expensive and using jackleg improvised tools is running a serious risk of trashing the barrel.

You've accepted the fact that you will almost certainly degrade the accuracy of the weapon to some degree or other, so it's a non-issue (assuming you don't do this mod and then squawk to Sig that it's not shooting well ;a ) You want the pistol reliable with plinking grade ammo, not just match ammo (I will be candid though, some of the match grade ammo is only a few dollars more a brick than the plinking grade stuff if you buy in bulk) so I'd say, go forward. Just think clearly about where you want to go with this and how you want to get there.