22rf chambering

[B Nettesheim]

Good morning
I have several 22rimfire barrels to chamber for a customer and reading through other posts people set the depth of the chamber off marks engraved into the lead bullet. I personally don’t see the repeatability of this practice, so I made a brass gauge that replicates the reamer angle thus being able to measure its protrusion once chambered. Once I get going how much engraving of the bullet do you look for ?
Sample barrel customer brought with

Reamer is a Nevius

 

[mudduck]

Read some threads on rimfire accuracy. Jerry stiller talks about it pretty good detail.

Here s a little info

22 benchrest chamberers

The question of what chamber to use is often asked by those looking for a solution to improved ammo performance without going through the trouble of lot testing. Many may expect or hope that ammo-specific chambers obviate the need for testing by simply using a certain make of .22LR match ammo...

www.rimfireaccuracy.com

 

[DirtySteve]

@skeetlee may be able to help you with this.. He does more than a few 22LR's..

 

[Ggmac]

If you use a match reamer , Win 52 ( my favorite) or any of the other available, they will engrave the bullet . Many variables, parallel sides , leade angles ,dia of actual case , etc . Its best to compare all the reamer data and pick the one that based on your customers ammo . Testing is the only fool proof way .
Sorry, no coffee yet .

 

[linekin]

It makes a difference what the rifle is being used for. For instance, you don't want a tight chamber in a semi auto or a lots of engraving. Also, if he would want to pull a live round out of the chamber with the extractors. Whats his intended use?

 

[Fuj]

I'll just throw this out there.....Just recently, I chambered checked at
the range 18 different brands, of which 10 were the supposed higher
end brand x's that run from $15 to over $20 bucks per box. Of those
ten, 3 did not ingrave, five I could feel and see light engraving and
two, the bolt closed hard with defined engraving. I have two different
lots and several years apart of RWS R-50. One engraves and one does
not, The one that does not engrave shoots tighter at 50 yards with no
tuner.

 

[B Nettesheim]

It makes a difference what the rifle is being used for. For instance, you don't want a tight chamber in a semi auto or a lots of engraving. Also, if he would want to pull a live round out of the chamber with the extractors. Whats his intended use?

It’s a fclass rifle

 

[B Nettesheim]

If you use a match reamer , Win 52 ( my favorite) or any of the other available, they will engrave the bullet . Many variables, parallel sides , leade angles ,dia of actual case , etc . Its best to compare all the reamer data and pick the one that based on your customers ammo . Testing is the only fool proof way .
Sorry, no coffee yet .

I’m starting to think that the right way would be to start with a lot of jam, shoot it, adjust chamber depth and shoot it…..
this reamer is basically a throating reamer

 

[Tad_Earhart]

Kevin Nevius that came up with the dimensions of that reamer typically uses light engraving. I forget the normal range he is looking for but a very friendly guy that I am sure would be more than happy to tell you what he is doing there. He is a forum member here.

Most people that want to play with engraving depth will run the chamber deep, then face back the breech face increasing the engraving depth until they get what they are looking for. A ton easier to play with things that way typically than to keep running the reamer in. One thing that cannot be discounted with a rimfire is finishing the leade after machining. The lead bullets and low power of a rimfire will take forever to clean up the leade of the chamber from just shooting alone and this will greatly affect the finished shooting product. Of course good machining of the chamber greatly reduces how much finishing is needed but almost every chamber will need something there. Depending on the leade angle, rifiling pattern, and internal dimensions, I typically shoot for somewhere between 0.135"-0.150" of stick out (measured off the back of a cartridge, pushed up to the point of touching in the chamber, to the breech face). This number will float around some based off of the length to O-give of the lot of ammo used( I see your gauge and it will work well after you figure out its relationship to average ammo length). There are people that have good shooting rifles with little engraving and heavy engraving but as mentioned in previous replies, what the rifle will be used for will greatly effect which way you go there. Personally, I have found things to be more forgiving with heavy engraving on BR rifles but that is not what everyone believes.

Edit to add: Whatever you decide on for engraving, please be sure to add a chamfer at the entry to the chamber at the breech face. The rim of the cartridge has a small radius at the corner of the rim to case body that will keep the rim from seating against the breech face. With it not seated against the breech face, there can be issues with obtaining consistent ignition and also tight bolt closure at normal HS dimensions of 0.043"-0.044" with some rounds/lots of ammo. A chamfer of 0.005"-0.007" in depth, at 45 degrees, with a slight polish off of the corners is plenty.

Tad

 

[Jonnyofalltrades]

I don't know F-class rules all that well, but having a live round stuck in the chamber doesn't feel great. Too heavy of engraving can make live round extraction a sometimes thing. Smoothing out the leade can help, but it doesn't take much to quit extracting again.

 

[B Nettesheim]

Kevin Nevius that came up with the dimensions of that reamer typically uses light engraving. I forget the normal range he is looking for but a very friendly guy that I am sure would be more than happy to tell you what he is doing there. He is a forum member here.

Most people that want to play with engraving depth will run the chamber deep, then face back the breech face increasing the engraving depth until they get what they are looking for. A ton easier to play with things that way typically than to keep running the reamer in. One thing that cannot be discounted with a rimfire is finishing the leade after machining. The lead bullets and low power of a rimfire will take forever to clean up the leade of the chamber from just shooting alone and this will greatly affect the finished shooting product. Of course good machining of the chamber greatly reduces how much finishing is needed but almost every chamber will need something there. Depending on the leade angle, rifiling pattern, and internal dimensions, I typically shoot for somewhere between 0.135"-0.150" of stick out (measured off the back of a cartridge, pushed up to the point of touching in the chamber, to the breech face). This number will float around some based off of the length to O-give of the lot of ammo used( I see your gauge and it will work well after you figure out its relationship to average ammo length). There are people that have good shooting rifles with little engraving and heavy engraving but as mentioned in previous replies, what the rifle will be used for will greatly effect which way you go there. Personally, I have found things to be more forgiving with heavy engraving on BR rifles but that is not what everyone believes.

Edit to add: Whatever you decide on for engraving, please be sure to add a chamfer at the entry to the chamber at the breech face. The rim of the cartridge has a small radius at the corner of the rim to case body that will keep the rim from seating against the breech face. With it not seated against the breech face, there can be issues with obtaining consistent ignition and also tight bolt closure at normal HS dimensions of 0.043"-0.044" with some rounds/lots of ammo. A chamfer of 0.005"-0.007" in depth, at 45 degrees, with a slight polish off of the corners is plenty.

Tad

I’m considering chambering it “short” lapping the throat, then testing some groups with his ammo. This action needs extractor cuts into the breech so I will chamber it slightly deeper and repeat the process. We can’t tune the ammo to the rifle so I am going to try tuning the chamber to the ammo.

 

[Ggmac]

I’m starting to think that the right way would be to start with a lot of jam, shoot it, adjust chamber depth and shoot it…..
this reamer is basically a throating reamer

Not really , each design has a different leade or ball seat . You cant change that without using a different reamer .

 

[Tad_Earhart]

A person can test things without the extractors installed on the bolt, and no slots cut into the barrel. You will just have to fingernail or pick the rounds out of the chamber which really isn't that bad if your just trying to test some things. I have done it quite a few times to test stuff and it has saved me from cutting slots in the wrong spot before when I needed to make a change.

It also can provide you with some insight to if your extractors/extractor slots are causing some accuracy issues. That can be a hard one to diagnose if your not looking for it directly.

Tad

 

[B Nettesheim]

A person can test things without the extractors installed on the bolt, and no slots cut into the barrel. You will just have to fingernail or pick the rounds out of the chamber which really isn't that bad if your just trying to test some things. I have done it quite a few times to test stuff and it has saved me from cutting slots in the wrong spot before when I needed to make a change.

It also can provide you with some insight to if your extractors/extractor slots are causing some accuracy issues. That can be a hard one to diagnose if your not looking for it directly.

Tad

Thanks
That is a great idea

 

[centershot]

I had an old time gunsmith that had a bunch of custom ground reamers. He was playing with the lead angle of the throat. I know that he said there was a difference. Just don't remember what he said was the best.

 

[Ggmac]

I had an old time gunsmith that had a bunch of custom ground reamers. He was playing with the lead angle of the throat. I know that he said there was a difference. Just don't remember what he said was the best.

What I found was that plated hi vel ammo had a preference and std vel lead was pretty much mixed and ammo specific.