I am going to build a 10/22 for my wife. She likes to shoot suppressed subsonic 22lr and we have had decent results with a Savage MKii at 100 yards (2"-3") using CCI STD Vel 40 grains at about 1050 fps. I do not want to use the 60 grain SSS as the best I ever got out of it was about 700 fps and lots of ejection port noise from the 10/22.

I can get a 1-9 here; http://www.eabco.com/store/pro...rel_Blue-1755-0.html . Pac-Nor makes 10/22 barrels in twists of 1-6, 1-8, 1-10, 1-14, 1-16 and a few more. What twist is best for subsonic 40 grain?

I want to minimize weight, but do not want a fiber or aluminum barrel with a steel insert. Does the .920 barrel out-perform the standard slim profile barrel simply due to its greater weight? Or will a well made slim barrel do just as well as the heavier ones? Thanks.

Ranb

www.rimfirecentral.com

look there for all the reading you will ever need on 1022's

quote:

I do not want to use the 60 grain SSS as the best I ever got out of it was about 700 fps and lots of ejection port noise from the 10/22.

I've had a lot of extraction and ejections problems with them too. The casing will come mostly to completely out of the chamber and stick requiring working the bolt and a helping finger. Wish I hadn't bought so many of them....

LWD

The main purpose of using a heavier barrel is that its greater mass does not heat up as rapidly, therefore allowing you to put more rounds down the barrel before heat starts to impact accuracy. This is obviously very important in centerfires, especially those shooting friction-generating jacketed bullets propelled by large quantities of powder. In practical terms, you can't shoot enough rounds down a .22 LR bore when target shooting to generate enough heat to impact the barrel. In other words, if a .22 LR's barrel is thick enough to give it reasonable stiffness, any additional weight is just weight.

Most factory .22 LR barrels use a 1-16" twist, which is perfectly adequate for the heaviest conventional bullets of 40 grains. Specialized heavy bullets may have different twist requirements. Much more important to accuracy than the rate of twist is the quality of the bore.

IME
you need <1:14 twist to properly stabilise 40gn subsonic
I would go 1:10 or 1:9
1:9 will give you more stability to the 40gn subsonic than you need as the minimum , but no harm in that.

I find the heavier a 22lr target barrel the easier it is to hold steady.

But unless you really want something "different" the 1:16" standard twist rate seems to work fine with the 40gr Subsonic ammo I've used.

My main source of amusement with the 60gr SSS ammo was being able to watch it run into empty pop cans at 50yards
through my 3-9X Rimfire scope

Just an additional " FYI " on the topic.

http://www.rimfirecentral.com/...Faster+Twist+Barrels

http://www.rimfirecentral.com/...Faster+Twist+Barrels

http://rimfireshooting.com/index.php?showtopic=7762
" I believe Remington used 1:14.5 " on some rifles, the 504 being one and maybe some of the 40X rimfires. Not sure how they arrived at that either "

Barrel Twist Calculator
http://kwk.us/twist.html

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

IMHO: A faster twist , might be of some benefit, shooting " Subsonic Ammo " @ longer distances ( 100+ Yards / Bullet Spin ; Stable ).

Are you shooting with wind flags? Have you tried some better ammunition like Wolf or SK, or even Eley or Lapua? Those two things will make a bigger difference than trying different twist rates.

I've used 1:16, 1:16.5, and 1:19 twist bores for 50 yard rimfire benchrest shooting. Most competitors have 1:16-1:17 twist barrels with more 1:16 than anything, and we only use subsonic match ammunition. The 1:19 barrel only shot well on hot days and was like a shotgun below 60 degrees. The 16.5 twist barrel on my rifle now has been doing very well from 45 to 90 degrees.

Shilen makes drop-in 10/22 barrels- check 'em out: http://www.shilen.com/rugerBarrels.html All are 1:16" twist so selecting the twist rate is an easy decision.

Above all... shooting better ammunition and using wind flags will give you the most gain in accuracy.

Here's another interesting thread:
http://benchrest.com/showthrea...Rimfire+Barrel+Twist
" Joe, the anschutz fortner biathlon is 1 in 14 they advertise it's accuracy to -20 degrees. "

http://www.nennstiel-ruprecht.de/bullfly/

Near the bottom of this page is a link to download a bullet stability calculator in Excel using the Miller Formula: http://www.accurateshooter.com...pin-rates-stability/

Not all, but most BR 22RF people use 16&17 twist.

What happens if you shoot at 100 yards on a cold day with the slower twists?

I don't target shoot at 100yds with my subsonic match ammo. I use a centerfire rifle.
I can't say what mine would do in that condition.

quote:

Originally posted by SR4759:
What happens if you shoot at 100 yards on a cold day with the slower twists?

At 50 yards I had very poor groups and elongated bullet holes on target. Not quite hitting sideways, but definitely not straight on. It also seemed like the wind conditions had more effect on the bullets too.