Using a 15/64" Drill bit to drill a chamber for 10/22

t_102

t_102

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I have been quite frustrated at my custom 10/22 since it would start jamming after 50 rounds. It seems to me that the chamber was drilled too narrow (Match chamber), and that any wax or carbon build up would automatically jam the gun. I built this 10/22 to be a "spray & fun" gun and accuracy is of no use for me. I am not a gunsmith and do not have a chamber reamer. I am considering to take a 15/64" drill bit and expand the chamber a little bit, which seems to be just a tad bigger than a standard "sporter" chamber.

Here's some specs for 22LR chambers:

Type --------- Length ----- Mouth Dia. --- Throat Dia. --- Taper @ Throat

Sporting ----- 0.7751" ------ 0.2307" ------ 0.2270"

Bentz -------- 0.6900" ------ 0.2270" ------ 0.2255" ------ 1.5° Taper

Match -------- 0.6876" ------ 0.2267" ------ 0.2248"

Win 52-D ---- 0.5800" ------ 0.2278" ------ 0.2248" ------ 2.0° Taper
Click to expand...

Now please pay attention to the Sporting type, mouth diameter of 0.2307. a 15/64" drill bit turns out to be 0.2343, just 0.003675"/0.093345 larger than the Sporter chamber.

I can imagine that the chamber may be able to shoot much much more rounds before it gums up.

My question is, if I did drill out the chamber to the 15/64" diameter,
1) Should I be worried about case ruptures?
2) Will the case not expand to full chamber diameter and case gas leaks to the rear? (In this case it might gum up the action)
 
the .22lr chamber should be .227" a from the base to the mouth #1 drill bit is more or less what you want(id make a stop collar so you dont go too deep) or just rent a normal .22lr reamer

the .2307 is something different idk what it is for
 
Using a drill to cut a chamber is a really good way to ruin a chambering job. A reamer will cut a very smooth surface; a drill tends to leave marks.
In a single shot zipgun, it probably doesn't matter. In a semi auto .22 a rough chamber is going to cause extraction problems.
There are several different specs of .22lr chambers. If your barrel is a target barrel, the chamber is likely tighter than on a regular plinking grade barrel.
An oversized chamber can result in ruptured cases.
Surely in the GTA there is a smith who could run a standard reamer into your barrel in 5 minutes. Have the barrel stripped out of the action.
Or, just watch the EE. New takeoff 10/22 barrels turn up all the time when folks replace them with aftermarket barrels.
You could even swap your barrel for a factory one, plus $, if yours is a target barrel.
 
Have you had a look into the chamber? Is it nicely polished? How about the feed area?

Also FTE or FTF? What rounds are you using?

-Grant
 
.003 is definitely WAY oversize. Letter A is .228 and would probably cut .001 oversize and would put you between bentz and sporting. A letter a reamer would be better
 
I'm going to say a drill bit is a bad idea. If you can find a chamber reamer, do it yourself. If not, let a gunsmith do it, or just buy a new barrel and sell this one.
 
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When I first saw this thread, I asked myself, "Is this guy for real or is he a Troll attempting to get a rise out of people?" Why would anyone even contemplate using a drill bit for a chambering reamer? However, that is based on over 55 years of working on Guns, and perhaps an explanation of WHY NOT TO is in order.

First of all, when chambering a rifle, a metal lathe is almost a "must." If you really know what you are doing, it is possible to cut a chamber by hand, but you better be good or you get egg shaped chambers. A lathe lines up the barrel axis with the chambering reamer.

A drill bit is not made with the exact minimum tolerances of a reamer. It can vary a bit on each cutting point surface and that makes the hole a bit "oblong" or out of round. Drill bits of various sizes are used for chambering, but for hogging out or removing a large amount of metal from the actual chamber, but everything is kept well undersized and chambering reamers are used after to bring the chamber to actual size. For a good job, a roughing reamer, a finishing reamer and a burnishing reamer is used to get a smooth chamber.

A drill bit cuts from the end. Therefore, when you push it into the metal, it gives VERY rough sides to the hole it makes. As it progresses downwards into the hole, it creates sort of a "Spiral" finish to the hole sides, and leaves a finish almost like very fine threads. IF a cartridge is fired in something like this, there is an excellent chance that the case will stick to the walls, due to the rough finish.

A reamer, on the other hand, is designed for tight tolerances to smooth out the sides of a hole after the hole is bored into the metal. It scrapes fine shavings off the metal, from the sides rather than the end, rather than cutting it, and leaves a smooth surface. A roughing reamer leaves a bit of a rough undersized chamber and is used to bring the chamber to approximate, though undersized shape. The finishing reamer then scrapes this chamber, removing only a few thousands of an inch of metal. The burnishing reamer is then used to polish and smooth the chamber to really make sure it is smooth and will allow the fired brass cases to extract. On high powered rifles, sometimes a throating reamer is used too.

Using a drill bit to enlarge your .22 rifle chamber is a VERY BAD idea. It is almost guaranteed to ruin the barrel, especially if you try it using a hand held drill.

It would be much cheaper, and more reliable, if you took the barrel to a gunsmith, and had him do the job.
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While I understand the rough marks may make the bullet case stick, would a slightly oversized chamber fix this?

buffdog said:
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When I first saw this thread, I asked myself, "Is this guy for real or is he a Troll attempting to get a rise out of people?" Why would anyone even contemplate using a drill bit for a chambering reamer? However, that is based on over 55 years of working on Guns, and perhaps an explanation of WHY NOT TO is in order.

First of all, when chambering a rifle, a metal lathe is almost a "must." If you really know what you are doing, it is possible to cut a chamber by hand, but you better be good or you get egg shaped chambers. A lathe lines up the barrel axis with the chambering reamer.

A drill bit is not made with the exact minimum tolerances of a reamer. It can vary a bit on each cutting point surface and that makes the hole a bit "oblong" or out of round. Drill bits of various sizes are used for chambering, but for hogging out or removing a large amount of metal from the actual chamber, but everything is kept well undersized and chambering reamers are used after to bring the chamber to actual size. For a good job, a roughing reamer, a finishing reamer and a burnishing reamer is used to get a smooth chamber.

A drill bit cuts from the end. Therefore, when you push it into the metal, it gives VERY rough sides to the hole it makes. As it progresses downwards into the hole, it creates sort of a "Spiral" finish to the hole sides, and leaves a finish almost like very fine threads. IF a cartridge is fired in something like this, there is an excellent chance that the case will stick to the walls, due to the rough finish.

A reamer, on the other hand, is designed for tight tolerances to smooth out the sides of a hole after the hole is bored into the metal. It scrapes fine shavings off the metal, from the sides rather than the end, rather than cutting it, and leaves a smooth surface. A roughing reamer leaves a bit of a rough undersized chamber and is used to bring the chamber to approximate, though undersized shape. The finishing reamer then scrapes this chamber, removing only a few thousands of an inch of metal. The burnishing reamer is then used to polish and smooth the chamber to really make sure it is smooth and will allow the fired brass cases to extract. On high powered rifles, sometimes a throating reamer is used too.

Using a drill bit to enlarge your .22 rifle chamber is a VERY BAD idea. It is almost guaranteed to ruin the barrel, especially if you try it using a hand held drill.

It would be much cheaper, and more reliable, if you took the barrel to a gunsmith, and had him do the job.
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Click to expand...
 
t_102 said:
My barrel is special. It is 28" and subsonics sound like it is supressed.
Click to expand...

All the more reason to take it to a Gunsmith who knows what he is doing.

You now mention that you are shooting sub-sonic ammunition. Is most of your jamming happening when you are shooting this ammunition, or does it happen when you also shoot regular ammunition?
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I find it difficult to believe that the match (i.e Bentz) chamber found on a typical 10/22 aftermarket barrel would in itself cause problems. My 10/22 with a Green Mountain barrel runs like a sewing machine on anything I have tried with it, including subsonic ammunition, with very infrequent cleaning. Exactly what kind of malfunctions are you encountering?

Whatever you do, don't ruin your barrel with a drill bit. If the chamber is legitimately undersized, the correct way to find out is to do a casting of it and take measurements. A reamer is the correct tool to use if required. Take the rifle to a gunsmith and have him look at it.
 
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