Rimfire Bore Erosion

One factor to consider, that was noted in tank main guns and anti-tank guns more than guns fired at a high angle. Guns fired at near parallel to the ground showed greater erosion on the lower surface of the bore due to gravity acting to pull downwards on even a spining projectile.
These were much heavier projectiles of course, but less dense than a solid lead bullet, at least till metals heavier than lead came into use for projectiles.
 
Outback said:
Tim

The rifle referred to is the Swiss rifle - Bleiker - Small front locking bolt - pin at 6 - part of the chamber is set into the action (it is still a normal type chamber, just there are 2 parts to it) - this results in a small expansion area as the primer end is a little larger in diameter - just pick up a spent case from the latest model, "Challenger" - in finals in Olympic SmallBore, these are the leading rifles at present - and yes this rifle has a finer residue and spread more evenly

Outback
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Thanks. There have been a few conversations about the Bleiker as to BR applications but so far none[ that I know of] have been used to build a rifle. I believe the barreled actions can be bought utilizing the Lilja but don't know if bare actions can be purchased. I do know that thy are quite costly. I understand the triggers are just beautiful. Is there any chance you can ever post an image of the bolt face or any part of the "floating" chamber ?
 
crb said:
So you are saying that the gun is making it's own lapping compound but this lapping compound is selective and only works on the bottom of the bore ? Even though the lap [ aka the bullet ] makes a full revolution in the bbl this selective compound only etches the bottom 2/3 of the bore.

That has not been my experience with lapping a large number of poppet valves. You can put one small spot of compound on a valve and lap the seat and when you clean the lapping compound off the parts you will have a nice lapped surface for the full 360 degrees.
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IMO
It’s because your only applying the grit (compound) on the bottom of the bore, it does the most damage while embedding into the lap (bullet). Say it takes an inch to embed, there isn’t much twist in an inch.

Lapping valves is a poor example unless your shooting steel bullets with non embedding lapping compound for powder. But I always used several dabs and rotated the valve with little pressure to distribute the compound before going to town with it.
Lapping barrels is a better example, and the cut-off mark some distance before the muzzle where the compound is embedding into the soft lead lap.

One other note.
Shooting a bullet after running a loose patch through a barrel doesn’t leave much of a smudge on the target, the second shot leaves a smudge all the way around the hole, evenly.
If the crud is blown out ahead of the bullet, why is the smudge even and darker?
 
I ran across an except from a book on forensics and crime scene investigation.
The subject was how to quickly ID whether a hole in wood work was a bullet hole or an old nail hole .
Bullets even the smoothest FMJ pick up and carry lead to be scrapped off on the edges of a hole in wood or wall paper.
Even FMJ bullets leave atomized lead in the bore due to powder gas erosion of the exposed base.
Same would apply to any thick fouling, and .22 rimfires seem to smoke up a bore quickly.
 
It’s because your only applying the grit (compound) on the bottom of the bore, it does the most damage while embedding into the lap (bullet). Say it takes an inch to embed, there isn’t much twist in an inch.

Lapping valves is a poor example unless your shooting steel bullets with non embedding lapping compound for powder. But I always used several dabs and rotated the valve with little pressure to distribute the compound before going to town with it.
Lapping barrels is a better example, and the cut-off mark some distance before the muzzle where the compound is embedding into the soft lead lap.

One other note.
Shooting a bullet after running a loose patch through a barrel doesn’t leave much of a smudge on the target, the second shot leaves a smudge all the way around the hole, evenly.
If the crud is blown out ahead of the bullet, why is the smudge even and darker?


You are right that the barrel doesn't twist much in an inch. I will say however that the smudge has to do with the leading part of the driving band on a RF bullet to "catch" some of the debris and carry it through the barrel and leave the smudge on the target. I had my barrel set back and re-chambered some 3/8" +- this year to limp by the rest of the season. The "wash-out" that was visible by the naked eye was at 6:00. It was obvious and detrimental to accuracy. The barrel setback and rechambering gave more life to the barrel (better scores and placement in matches) but is temporary. The gun still doesn't shoot like it did when the barrel was newer (bought it used). Gravity leaves the debris in the 6:00 position and air pressures push some (how much?) out the barrel ahead of the bullet and the rest of the stuff just simply slowly laps the barrel until it isn't competitive anymore. I have no data on the number of rounds it takes. I noticed a loss in accuracy a year + ago and started refining the problem. It will be a new barrel this winter. Hope This helps with all who have been seeing loss of accuracy.

Carp
 
Tim
Photo of Bleiker "Challenger" Bolt with 6 oclock firing pin - Bolt is 3.75 inches long & Bore Deposits

_22-Bore-Deposits.jpg

Bleiker-Bolt.jpg
 
thanks for the photos how does it load
feed ramp, magazine? any pictures?
 
Tom C,

No magazine - the loading port is on springs & drops down as the bolt is pushed forward
 
beautiful bolt. i'll do some searchs. what price
range they run in. 5k-10k.usd?
 
Outback said:
Tim
Photo of Bleiker "Challenger" Bolt with 6 oclock firing pin - Bolt is 3.75 inches long & Bore Deposits

View attachment 8746

View attachment 8747
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Outstanding, thanks. Does the bolt handle act as a lug as well or just the front 2 lugs? Any chance of an image of the breach end? This has been very informative. By the way I know several of the Aussie intl team use Bleikers, you one of them? Understand if you defer.
 
I bet I know somebody that could tell you all about the reason for the way the throat erodes. I thought he would chime in and tell us, but he must have been banned or something.
 
Tim,

Not easy to takephoto of the breach area - the action is made of a number of parts - bolt, trigger set, Breach part, back part, underneath plate that holds the lot together, top rail - the engineering pecission is so tight there is virtually no play - has a special anodised hardened surface on the bolt - the bolt handle acts as a safety lug - you have to be careful with the type of ammo used as the tolerances are so tight - has a liking to Eley red & black

In 99 shot at Camp Perry
 
ob is that your bleiker? if so what did you use before that?
 
Tom,

My Bleiker Barrel Action is set up in another Brand stock - have used the AN2000 in this stock for many years for great sucess with a Broufgton 5C barrel the same profile as Bleiker, just 2 Ins shorter to compensate for the longer action of the AN2000
My wish would be AN2000 with firing pin at 6 - they are so easy to change barrel & reset - different barrels for various wind & weather conditions
 
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