For maximum accuracy, if you close the bolt and then open it and extract the un-fired round should there be an imprint of the beginning of the lands on the bearing part of the bullet ? or should there be sufficient distance to the lands that the bullet i'snt marked in any way ?
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should a 22lr bullet be pushed into the lands ?
- Thread starter barronian
- Start date
This is a good question.
I am going to say, yes but not necessarily.
This is just one of those barrel parameters that has usually a positive effect on accuracy.
Maybe similar to thin versus thick barrel. Thin might make similar or even better groups due to improved harmonics with a lot of tuning but usually the thicks pull the longer straw and have other perks.
I am going to say, yes but not necessarily.
This is just one of those barrel parameters that has usually a positive effect on accuracy.
Maybe similar to thin versus thick barrel. Thin might make similar or even better groups due to improved harmonics with a lot of tuning but usually the thicks pull the longer straw and have other perks.
It depends on what your goals for the rifle are. Most all production rimfires have chambers that are way longer than they need to be. This is to ensure they function and digest whatever the end user feeds it to keep customer service calls to a minimum, so you’ll never see the lands imprinted on the bullet.
Match chambers do imprint the bullet and this is why many platforms will not reliably extract loaded rounds. The extractors aren’t sprung enough to maintain grip on the casehead to overcome the resistance of pulling the bullet out of the lands. If they were, this would create ejection issues.
MB
Match chambers do imprint the bullet and this is why many platforms will not reliably extract loaded rounds. The extractors aren’t sprung enough to maintain grip on the casehead to overcome the resistance of pulling the bullet out of the lands. If they were, this would create ejection issues.
MB
Custom match 22lr chambers properly headspaced usually have a slight crush or push into the lands.
All the CZ 455 group buy barrels we just did have a Lilja match chamber headspaced to .041 which gives a slight push into the lands. Accuracy is excellent and not picky with ammo.
For example, factory CZ barrel had .048 headspace and no push into the lands. Very picky with ammo but loved FGMM 922A.
All the CZ 455 group buy barrels we just did have a Lilja match chamber headspaced to .041 which gives a slight push into the lands. Accuracy is excellent and not picky with ammo.
For example, factory CZ barrel had .048 headspace and no push into the lands. Very picky with ammo but loved FGMM 922A.
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But is this obligatory for maximum accuracy? Isn't it usually enough that the bullet is near the lands?
so is it worth taking a production 455 varmint barrel and shortening the distance to the lands ?
Yes. Extremely. If you can do it yourself then sure. If you have to pay gunsmith fees your better off getting a new match barrel with a properly fitted tenon, chamber and headspaced to your action
The bullet being engraved by the lands after ejecting an unfired round is one thing, not being able to extract an unfired round without shooting becase the bullet is stuffed into the lands is something else altogether, and the fine line between the two can change substancually between different brands and types.
I would favor positive extraction over small improvements in precision.
I would favor positive extraction over small improvements in precision.
Actually, it depends on the reamer design when it comes to bullets being engraved by the lands. I never have a chamber reamed when I headspace a barrel, which is SOP for Vudoo. Generally speaking, headspacing at .041 (or at any dimension) doesn’t mean the bullet will be engraved.
MB
I agree, headspace all depends on what bullet you predominately will shoot. 0.041 is pretty standard headspace for 22lr match chamber if you don't have a specific bullet you'll be shooting
Match chambers are cut so that the bullet is engraved by the rifling/engages the lands.
Doing so provides the most consistent results, as it aligns the cartridge/bullet with the centerline of the bore.
With the nose engaging the lands the bullet starts in essentially the same chamber position/location for each shot.
For precision shooting every round needs to start in the same location in order to obtain similar trajectories.
With a loose/sloppy chamber that can't happen. With the bullet snugged into the lands, you end up with better results.
The 455 Lilja with the EPS chamber engraves about 3/32 inch.
455 Shilen cone breach engraves a bit more
Doing so provides the most consistent results, as it aligns the cartridge/bullet with the centerline of the bore.
With the nose engaging the lands the bullet starts in essentially the same chamber position/location for each shot.
For precision shooting every round needs to start in the same location in order to obtain similar trajectories.
With a loose/sloppy chamber that can't happen. With the bullet snugged into the lands, you end up with better results.
The 455 Lilja with the EPS chamber engraves about 3/32 inch.
455 Shilen cone breach engraves a bit more
? i thought that for rimfire headspace wasn't related to bullet seating depth at all ? aren't they independent ? one from the breach face back to the bolt face (rim recess) and the other from the breach face to the lands ?
nice illustration pictures ! in my 455 factory barrel the round will just drop right in ...Match chambers are cut so that the bullet is engraved by the rifling/engages the lands.
Doing so provides the most consistent results, as it aligns the cartridge/bullet with the centerline of the bore.
With the nose engaging the lands the bullet starts in essentially the same chamber position/location for each shot.
For precision shooting every round needs to start in the same location in order to obtain similar trajectories.
With a loose/sloppy chamber that can't happen. With the bullet snugged into the lands, you end up with better results.
The 455 Lilja with the EPS chamber engraves about 3/32 inch.
455 Shilen cone breach engraves a bit more
When doing 10/22’s I would find the ammunition that the barrel likes the best. Then I would remove material from the front of the bolt until the headspace was at the minimum for the rim thickness of the ammunition the barrel liked. The rims on rimfire ammunition can vary quite a bit between manufacturers so for maximum accuracy you want the minimum headspace to reduce slop and increase consistency.
Traditionally for a true match chamber on a single shot 22 lr the throat is cut so that the leading lands of the barrel engrave about 1/4-1/2 of the 2nd driving (sealing) band of the bullet. This method will (9 times out of 10) produce the most accuracy. I have had many barrels set up this way, and also some with the lead just touching the front of the first driving band, and some just just off. All have been great shooters.
I had one Shilen Ratchet barrel that was phenomenal shooter but the action had feeding issues. It was set up to engrave an Eley EPS bullet to the 2nd band. During the troubleshooting of the feeding one of the first things was to lengthen the throat to just touch the bullet (did not resolve the feeding issue, another story for another time), but the accuracy dropped ever so slightly. Meaning I was no longer able to get those groups in the 0.0XX as often or as low. The average accuracy did not suffer but the very top end razors edge did ever so slightly. This is the only first hand experience I have with moving a throat on a extremely accurate 22lr barrel.
Hope this helps answer your question...
I had one Shilen Ratchet barrel that was phenomenal shooter but the action had feeding issues. It was set up to engrave an Eley EPS bullet to the 2nd band. During the troubleshooting of the feeding one of the first things was to lengthen the throat to just touch the bullet (did not resolve the feeding issue, another story for another time), but the accuracy dropped ever so slightly. Meaning I was no longer able to get those groups in the 0.0XX as often or as low. The average accuracy did not suffer but the very top end razors edge did ever so slightly. This is the only first hand experience I have with moving a throat on a extremely accurate 22lr barrel.
Hope this helps answer your question...
No, not on a CZ. The face of a rimfire bolt action rifle, like the CZ, is fixed based on where it is located when the bolt handle is locked down. There are 2 ways to adjust the CZ. 1st is by removing material from the barrel shoulder which in turn makes a longer barrel shank which then gets closer to the bolt face. The other method is to slide ring shaped shims over the bolt body in front of the bolt handle. This effectively pushes the bolt body forward by a few thousandths, depending on the shim thickness.
Well... i sat the barrel back a bit and shortened the chamber ... SK Rifle Match now just engraves a tiny little bit.... and the results are ....
inconclusive.
when i now shim the bolt to get the headspace down from .047 to .043 i think i'm seeing better grouping Iie instead of a .8 MOA scatter at 50m ill get two tight groups but still .8 MOA in total. I'm pretty sure that this is my fault and not the gun - if i could be more consistent i would prob have one group of 0.3 MOA. The chamber is obviously still a sport chamber and not a match chamber, ie the round will just drop completely in under its own weight.
Off on work travel now so i wont be able to play further before i get back in a few weeks :-(
inconclusive.
when i now shim the bolt to get the headspace down from .047 to .043 i think i'm seeing better grouping Iie instead of a .8 MOA scatter at 50m ill get two tight groups but still .8 MOA in total. I'm pretty sure that this is my fault and not the gun - if i could be more consistent i would prob have one group of 0.3 MOA. The chamber is obviously still a sport chamber and not a match chamber, ie the round will just drop completely in under its own weight.
Off on work travel now so i wont be able to play further before i get back in a few weeks :-(
I remembered this thread so I dug out rifles that are target oriented. A 1928 Mod. 52 Pre-A engraves through most of the driving band. An early '90s Browning 52C Sporter reproduction (made by Miroku) engraves through the driving band. A '67 Anschutz 54 Match 1413 (Super Match) engraves all of the driving band. Lapua Center-X was used in all cases. My new T1X does not engrave any of the driving band as best I can tell.
The 52s and the 54 both have dual extractors, the T1X is a single. None of the three have ever had a failure to extract. The pre-A 52 shows erosion at the throat. The 52 repro has about 500 rounds and looks as new. The 1413 is as new. My guess is the original owner never fired it. I've put about a hundred rounds through it. It is the most accurate of the three but it is a single shot and physical problems make single loading a PITA for me. Thus, I never pursued it's use to find it's capabilities.
There must be a point to this and hear it is. I'm confident a T1X will shoot in the low threes, maybe even the high twos. That makes it competitive in any NRL 22 match. That's amazing for a rifle that I paid less than $440. for. I'll keep working at it.
Ravage88, your comments would seem to indicate that the Vudoo is chambered not to engrave. Is that the case?
The 52s and the 54 both have dual extractors, the T1X is a single. None of the three have ever had a failure to extract. The pre-A 52 shows erosion at the throat. The 52 repro has about 500 rounds and looks as new. The 1413 is as new. My guess is the original owner never fired it. I've put about a hundred rounds through it. It is the most accurate of the three but it is a single shot and physical problems make single loading a PITA for me. Thus, I never pursued it's use to find it's capabilities.
There must be a point to this and hear it is. I'm confident a T1X will shoot in the low threes, maybe even the high twos. That makes it competitive in any NRL 22 match. That's amazing for a rifle that I paid less than $440. for. I'll keep working at it.
Ravage88, your comments would seem to indicate that the Vudoo is chambered not to engrave. Is that the case?
No sir, the Vudoo chamber engraves the driving band but the design of the forward part of the chamber allows release of the driving band for extraction/ejection of loaded rounds. The 52D (.580 not including the lead angle) is the shortest/tightest of Match chambers in existence and the Vudoo chamber (.605) is only slightly longer. Other Match chambers you mention are longer than the Vudoo chamber.
MB
