.22 barrel twist rate

Being I'm working on .22 barrels and looking to buy a few blanks, what is the best twist rate for barrel length 4.8" to 5"??? I do like using the SK Match rounds, also the standard yellow box. I do have some SK rifle match that a little higher in velocity. Lilja has a .2215 by .217 and .2200 by.215" in 16" twist.

I've run across comments that suggest a bit faster is a good idea. Shilen has 14 and/or 15, and oversize blanks? Or maybe Lilja.

That said, I made a barrel for my M-41 using a piece of 416 and a liner made from a cut off from a 1-18 Lilja. An oddball I bought off the shelf to play with Shorts in a rifle. Later reamed it out for LR and it's shot very well even at 200 yds. The 41 shoots quite well at 50 ... from a rest ...

I'm working on my Home made .22 conversion. The barrel is one piece except I'm sleeving the unit go get it rifled. After getting all the needed dimensions I want to make a one piece barrel from top maker blank but I'll need 1.90" OD. I just put an Anschutz barrel on Adams Nelson, I'll see how well it shoots. However I don't know the twist rate, .216" gauge pin fits in the bore but .217" will not.

I’ve read 1:16.5 twist for Anschutz barrels.

From old Jerry Keefer(RIP) Post:

Bullseye old timers remember the Multi Groove 22 LR barrels of the early KART Conversions..Floyd Aikman used multi groove in most of his 41 barrels.. Here is a brand new one, I just received today.. So, they are not extinct.. .216 bore .222 groove,  with 12 lands and grooves. Destined for a Hammerli 208s..

Froneck wrote:Being I'm working on .22 barrels and looking to buy a few blanks, what is the best twist rate for barrel length 4.8" to 5"??? I do like using the SK Match rounds, also the standard yellow box. I do have some SK rifle match that a little higher in velocity. Lilja has a .2215 by .217 and .2200 by.215" in 16" twist.

Hi Frank,
I had a friend make a 1911 .22 conversion barrel using the .215" bore Lilja blank. It works fine and is accurate.
I think the chamber is more important in BE for feeding. I've measured old vs. new CCI and the cases are .001" larger in diameter.
FWIW: My GSP has a huge chamber and it's the most accurate barrel I have (shot a 547 in Free Pistol with it).
Hope this helps,
Wes

Quite a while ago I was making the 41 barrels for Floyd Aikman I knew him quite well!
 I was always thinking of using a tapered pin reamer to taper the chamber for the .22 so it could load easier. Being the conversion mags have short lips the tapered chamber might help. A good idea that before removing the barrel I try a tapered reamer. Was going to remove the barrel so if I screw it up there is no loss!
 Do you know the diameter of the chamber in your GSP??

Have you looked at a 22”Bentz” chamber.  It was developed for Semi-auto rifles but might make a good compromise.

https://4drentals.com/product/22-lr-bentz/

My 'custom' M-41 barrel has a Bentz chamber. It's what I have... ***

Passes the 'plunk' test ...

*** The only other 22 RF reamer I have is a 'Calfee' ... .225 dia and a 2deg leade.

The "standard" Kart barrel was leftover Marlin Micro-Groove barrels.  So, yes they are probably still available.  

Some of the very early Karts had various other makes but apparently the Marlin barrels left over's were available and tended to shoot plain lead .22 bullets pretty well.

Looked at the Bentz reamer site. I'm thinking that after chambering with the Clymer reamers I have (rougher and finisher set) I can use a #3 taper pin reamer that has max diameter of .2294 and taper at .0208/inch will give me a short taper to possibly make the conversion functioning better. I have a Nelson barrel I didn't disassemble yet. Might try that tapered reamer in it.

Why fix a problem you don't have?

And I thought the OP question was twist rate.

Yes question is twist rate because I need to purchase a few barrel blanks. I just re-barreled a Nelson with a barrel the customer supplied and know nothing about it. Friend tested group size for me and said it functioned 95% of the time. Best group was from CCI standard (only type CCI tested) other lower velocity ammo like SK standard (Yellow box)SK pistol match and pistol match special (green box and SK rifle match (red box) I use SK, friend provided the CCI. Best group size was with CCI, next was SK rifle match. Seems the higher the velocity the better the group!
 OK I tested the barrel in my Nelson new never fired prior to this test with 15lb Wolff main spring (firing pin was modified) and Wolff variable rate 6.5lb 41 recoil spring. As I mentioned I was told it functioned 95%, I plan to put the Nelson an a dedicated frame so when chambering was mentioned I got off on a tangent. I want 100% In addition I have a home made conversion that is on a dedicated frame but need to remake the barrel that I screwed-up. But that too will be on a dedicated frame!
 So yes I want the best twist rate on the best barrel bore size and chamber the gun to function 100%. My 1911 does and the 1911 I built for Adam would shoot a complete season in matches without and alibi!!
 Since accuracy is the main issue I'm interested in the best twist rate, bore size and chamber dimensions that will give the best results. A while ago Adam told me the AMU smith re-barreled a 208 with a tight chamber, it shot nearly a one hole group at 50 yards but would not function well so chamber size was increased. Maybe I'll never shoot a 100-10X at 50 yards but I know someone very well that did a few times with .22 and 45acp  

Greetings,

The photos are of 50 yard group of a custom Pardini SP barrel I machined. The owner requested a 6" barrel length.

I used a Douglas Chrome-Moly 22lr blank with 16 twist.

I have the barrel blanks heat treated to 40 HRC.

I chambered with a JGS Tools "Bentz" profile reamer.

I have used 14 twist; but, could not find any appreciable improvement.

I tested with CCI SV and TENEX.

Cheers,

Dave

The standard among .22 rifle shooters is a 1-16" twist. Through the years, primarily led by benchrest shooters, there have been trials of other twists with a consistent return to the 1-16"

Bentz is probably a best bet because it is meant to cycle semi-autos. Any of the Calfee, anschutz, winchester 52 reamers with rim cutters will not work on a pistol because they force the bullete into the rifling. 

Unless one is inclined to reinvent the wheel, don't

Ron

Some redesign is necessary! I'll bet the 1911 built by the top builders are slightly different than what Browning did. Browning didn't design a tack driving match pistol. It simply was a reliable semi-auto for combat use. Olympic shooters have the same frame in the .22 and .32 pistols. Bullseye shooters are looking for the same so the .22 conversion is popular with High Master shooters that are wining matches.
 I have a Nelson and a few other high end target .22s and over the years had or worked on countless others.
 When I got the Nelson I put it on a frame without the spring and quickly noticed if the slide is closed slowly the round will fall out of the gun. When the round is released by the magazine lips it is nearly 1/4" short of the chanber! Yet ALL of my other .22s the bullet is in the chamber up to about the .223" diameter. The point radius seem to have been designed to allow for the angled approach into the chamber from the mag.
Being the .22 conversions don't have the bullet in the chamber when the round is released it's depending on the speed of the slide. When the springs that would allow the conversion to function were used and loading by inserting a loaded magazine and releasing the slide stop the gun would not load. Bullet would hit above the chamber opening at 12 o'clock! But if the slide were drawn as far back as possible then released the increase in slide speed allowed the round to chamber! Therefore in my homemade design I moved the barrel back and used Colt Ace magazines! However I do have the Nelson and my intent is to make it reliable so possibly making the chamber opening larger will help. That is why I want to try increasing the taper. In the past I chambered quite a few .22 barrels using a 2 piece .22 reamer from Clymer that worked quite well. Since others pointed out reamers are available with a taper so now I'll check the Clymer I have for taper and compare it to other available.
 I might point out it's not only me but others like Pardini and others like myself that modify the existing designs to get better results. If that were not necessary we all would be driving Model T autos.

Frank,

On all my own conversions I use the EGW high magazine catch and Colt Ace magazines. I file the feed lips to clear the ejector and reshape the feed lips. The cartridge feeds more inline with the chamber. No bullet deformation!

Jon

Thanks Jon. I'll call EGW and get a few High Magazine catches. be nice to have a couple in my 1911 parts box. And one to try in the conversion.

My 'Calfee' reamer is a .225 2 deg *THROATER*.

I can cut what I want ... but, mostly, it was cheaper...

Frank,
Your proposal to open up the mouth of the chamber can very quickly result in detriment to case head support and poor ignition. The limit on that transition is a very light radius or edge break of .005-.007 or less.
I cannot say firsthand but it does seem 'that Jon's suggestions of raising the centerline of the cartridge by mag placement and other mods will make it feed far more reliably without compromising the chamber.

If the Bentz reamer will open the chamber to .2278" and I open the end to 2294" at a taper of .021/inch The Chamber at the opening will be .0016 larger Than the Bentz opening for an about .100" being a taper it will be about .0008" larger at about .050" into the chamber. The transition will be smooth rather than an abrupt change .005" to .007 will be though I will still round the edge. .0018" is not going to change anything and I'm willing to bet chamber wear over time is greater than .002" Not to mention manufacturing tolerance. Though I don't know the actual dimensions of my Clymer reamer nor what the Nelson barrels are either but putting a #3 taper pin reamer in a barrel I plan to remove so a to test the results shouldn't be a problem. I may improve loading and not effect accuracy or alter accuracy so that it's a wrong modification. I personally don't think it will increase group size but will find out!
 For example the Floyd Aikman Lilja barrel put in my homemade IZH pistol was shot by me for a few years then my son for 9 years, It shot quite a few 900 matches and practice 900s at the club each week. Plus my son shot everyday after school! I went thru cases of CCI ammo! I'm willing to bet the chamber is worn more than .002" larger than when Floyd chambered it yet it still shoots Nickel size groups at 50yards!