I got a 10/22 from a friend of mine that was a basket case when I got it. Really just a receiver, bolt and trigger group. Got a barrel and stock and put it all together. Did not use it much until I got involved with Appleseed.
Anyway, it was giving me a problem with light or non-existent firing pin hits. So bad in fact that we had to use a loaner rifle. Again my thanks to RickB for the loaner rifle.
Got down to trouble shooting the beast yesterday. Headspace was a little excessive. Lapped the bolt face square and got the HS to 0.044". Still had problems.
Got to looking at the design in earnest. The relation of the hammer to the back of the bolt is controlled by the length of the barrel trunnion into the receiver. Using Prussian Blue I determined that the hammer was striking the base of the bolt, below the bolt stop cutout.
I found a spacer from an old air cooled VW rocker arm on my bench. It has a slightly larger ID then the trunnion of the barrel so the barrel went inside it with ease. I had to grind tho OD down to match the barrel. When I got it finished and reinstalled the barrel it went through 75 rounds without a hick-up.
Hope this type of info may help others.
Doug
Thats awesome. Nicely done!! O0
Wow, VW parts in 10/22 -
Take a look on rimfirecentral.com - the stickies for the 10/22 - in one of them they chamfer the rear of the bolt from square to a radius - this allows the returning bolt to contact the hammer higher up; Archimedes takes over and the hammer goes down with less force (through, of course, a greater distance.)
I've eyed it but not tried it, but the idea is you could even cycle with low-energy .22's.
Yea, I'm going to radius the rear of the bolt for my next trick.
Did the auto-bolt release last night. Works slicker than a greased door knob. ;D
Took it to the range today. Got it sighted in for 25 yards. 200 rounds and only one failed to fire. Had a good firing pin hit so I'll take that one as bad ammo.
Quote from: gunville on April 25, 2009, 11:17:33 PM
Wow, VW parts in 10/22 -
Take a look on rimfirecentral.com - the stickies for the 10/22 - in one of them they chamfer the rear of the bolt from square to a radius - this allows the returning bolt to contact the hammer higher up; Archimedes takes over and the hammer goes down with less force (through, of course, a greater distance.)
Seems to me that the hammer would go down with GREATER force, since the bolt weighs less, and would therefore be moving with greater velocity.
Anyway... I seem to recall that they claim a quicker recycle time for this mod. I've been debating doing it myself.
The hammer and firing pin are not altered nor affected by the bolt radius modification. The modification only changes the amount of force required to knock the hammer back into the locked position.
The stock bolt has about a 1/8" radius (or less) at teh bottom, back of the bolt. This is the surface that cams the hammer back as the bolt travels to the rear when the rifle is fired. By making the radius larger (misnamed chamfer for this mod) you raise the point on the hammer at which the bolt applies the force supplied by the cartridge thru the bolt when cocking the hammer. This new point is higher up on the hammer, so it increases the mechanical advantage the bolt has when compared to the hammer, there by reducing the power needed to cock the hammer.
No mods are made to the hammer or firing pin. It is said to reduce the chances of stovepipe jams.
Quote from: douglas34474 on April 27, 2009, 04:59:42 PM
It is said to reduce the chances of stovepipe jams.
So far, with the new VQ Exact Edge extractors on both of my LTRs, no stovepipes have been noticed. ~700 rounds through one and ~400 through the other since the installation.
Glad to hear you got that pesky gremlin exorcised from the 10/22! A less patient man (myself) would have sent the rifle down range to use as a target stand.
Quote from: dwarven1 on April 27, 2009, 04:06:27 PM
Seems to me that the hammer would go down with GREATER force, since the bolt weighs less, and would therefore be moving with greater velocity.
Anyway... I seem to recall that they claim a quicker recycle time for this mod. I've been debating doing it myself.
The rearward force of the bolt is determined by the power of the .22 round; this force remains the same regardless of the mass of the bolt. (Force = Mass * Acceleration - if you decrease the mass the instantaneous velocity increases, but the force remains the same.)
The hammer is a lever.
The win comes from increasing the momentum arm on the hammer. For the hammer to reset, the moment on the effort (bolt) side has to exceed the load (spring) side:
F1*L1 > F2*L2
F1 being the force of the bolt (actually the .22 round),
L1 being the length from the hammer pivot pin to where the bolt contacts the hammer.
F2 being the force of the hammer spring,
L2 being the length from the spring contact to the hammer pivot pin.
If the hammer doesn't reset, it's because F1 is too low - say from subsonic or CB's.
By moving the contact point of the bolt up, you increase "L1". This makes up for the decrease in F1, allowing the lower force to return the bolt. (Archimedes comes through "Give me a lever long enough and a place to stand I shall move the earth.")
(Edited - per Moggart's superior physics grade.)
gunville
Unless I'm mistaken (and that has happened before ;D) you need to add the mass of the bolt into your equation. The recoil spring adsorbs some of the force from the cartridge, but the force required to overcome the inertia of the bolt is the major factor in a simple blow back design.
I believe that F1*L1 > F2*L2 is true but F2 = recoil spring + the force required to move the bolts weight. It's been a while since I calculated force equations, but I believe you get the point.
But your point is well taken. The amount of weight removed by increasing the radius of the bottom of the bolt would not be enough to effect the system, and moving the contact point higher on the hammer reduces the force required to operate the system. Thus increased reliability with standard velocity ammo.
douglas34474,
You are thinking of the recoil forces on the bolt itself - the equation refers to the hammer, not the bolt. (And descirbing the bolt recoil would use straight force, not moment arms.)
Let me clarify; the F1*L1 and F2*L2 refers to moment arms on the hammer - which is a lever.
F2 is exerted by the spring in the back of the hammer on the trigger group.
F1 is exerted by the bolt.
This F1 is dominated by the newtonian "equal and opposite" force of the bullet leaving the barrel and reduced by the recoil spring on the charging handle. Inertia (mass) of the bolt being relatively minor compared to this spring. Remaining force is exerted on the bolt stop and exerted as "felt" recoil. (Weight of the gun matters as well.)
if you just reshaped the bolt to increase L1 while keeping the mass of the bolt the same, (to assure no impact on F1) you would still reset the hammer with a lower power round (i.e. less recoil force.)
Where's my pocket protector?
Doug,
Glad you got your 10-22 working. That will make your grandson happy! The LTR that I loaned him had three mods--radiused bolt, an aftermarket (sharper) extractor, and auto bolt release. The radiused bolt does help cycle standard velocity ammo. The sharp extractor cured stovepiping. The auto release I don't like. If you need to do a quick cleaning (without disassembly) then every time the rod taps on the bolt it closes! The standard Ruger bolt is really fast and easy to manipulate (if you have practiced).
I have a second LTR that looks identical but it has none of the above mods--and never needed them. Every rifle is different.
RickB
Well, I've got it just about where I want it! O0
Did a trigger job; I hate heavy triggers.
Narrowed the profile of the Firing Pin for better hits; no more failures to fire.
Radiused the bolt; feeds just about anything now.
Did the auto bolt release; I really like it.
Pinned the firing pin so it does not ride up and miss the cartridge; what got me going on this thing to begin with.
Put it in a new (to me) walnut stock with oil finish.
Went to the range yesterday. At 25 yards I was taking the center out of the 1 inch squares.
Not one failure of any kind. 8) 8) 8)
Now.. when's the next Appleseed? ;)
Doug,
ItsAnSKS is just about finished lining up two Appleseeds this summer--one in St. Augustine and another in Ft. White (near Gainsville).
If they are too far we have 5 more this year at Hernando and Myakka--starting in October.
RickB
I've already written ItsAnSKS about the Ft. White range trip.
Hernando, Ft. White or St Augustine are all about the same drive for me. I'm already planning for the Hernando event. O0
I've been trying to find a range in the Ocala area with out any luck. :( This County just does not have a facility that can handle an Appleseed.
doug,
What'd you use to radius the bolt?
How far up did you bring the engagement point?
I lapped it in by hand with a diamond sharpening stone. I have several different ones I use of various sizes, shapes and grits to work with, along with Hard Arkansas and India stones. I just sit an watch the TV as I work. Drives the wife a little buggy. ;D
When I took my machine shop training the gent that was my instructor recounted stories from his instructor. My instructor's instructor took his training in Germany. After a four year apprenticeship, for his final he had to make a machinists vise using only a hack saw and a file. The thinking was, if you can't do it by hand, a machine will not help you. <:)
I left about 1/16" of the flat on the bottom, back part of the bolt and made a smooth transition from there.
I have some Agila SSS (Sniper Sub Sonic) rounds. They are 60 grain bullets loaded into a 22 SHORT case. To look at them, they are 3/5 bullet and 2/5 case. They will cycle the action now.
Shooting target or standard velocity ammo it gives me no problems.
HTH
Douglas
Do the Aguila sub sonic bullets stabilize in the 1:16 twist of most 10-22 rifles? When I tried them the groups opened up to about 5" at 25 yds. They smell funny also. If they work for you I have some ammo you are welcome to. A fast twist barrel is available for the 10-22 that should stabilize the longer bullet. However, $200 for another barrel was not going to work for me.
willorith;
I have not really shot to see how they group. But my experience with longer bullets in my 22 Hornet mirror yours with the SS.
I bought 500 Nosler 45g ballistic tip bullets for my 22 Hornet. It has a 1:16 twist. These bullets will not stabilize at that twist. Groups are 3X what I get with Sierra 40g Hornet bullets.
I just found it interesting the the old 10-22 would even cycle them. 8)
Quote from: dwarven1 on April 28, 2009, 11:40:13 AM
Quote from: douglas34474 on April 27, 2009, 04:59:42 PM
It is said to reduce the chances of stovepipe jams.
So far, with the new VQ Exact Edge extractors on both of my LTRs, no stovepipes have been noticed. ~700 rounds through one and ~400 through the other since the installation.
2k rounds through a 10/22 using the stock extractor, zero stove pipes.