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22 LR Average Group from your gun


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36 minutes ago, No i deer said:

I just watched some videos on the CZ 457 lr 22 rimfire and it sounds great..

Go on the sportsman guncentre website..

In to the gun and scroll down to see the 3 videos..

It looks to be the dogs dangleys 

Cz457 mtr - I did quiet a bit of researching and I think it’s a very good factory gun for the money (before anschutz territory) as I mentioned before the action is used by dolphin guns for their elr 22s, I actually spoke with mik there about a lijia barre for it, and he said mine looks to be shooting well and even the lijia probably couldn’t beat the way it’s shooting currently...

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Well today was a bit of a disappointment, i has to abandon my testing due to getting a call from from next door farm with hare coursers , so it was a throw the rifle back in its case and in back of truck and then spent the next 2 hrs  sat blocking a track off ( there was 8 of us from 3 farms all Blocking and entrance/exit ) until the police turned up . Anyway I was bored by then so called it a day . I had jobs to do in afternoon anyway , soooo going to have  another go tomorrow . Today started so well to .

so much for no excuses ☺️

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Very Gucci 🤩

I shoot f class with Mik..

The CZ 457 LR on them videos sounded very appealing with the 20 inch barrel..

I don't want a long barrelled 22lr.

How much would that 22 Mik built cost....

Shame your testing was interrupted 🙄

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Got this to have a go at some paper punching. 

Initial trials are proving fruitful with SK match. Though to be fair shooting at 100 yards in a breeze and 2 degrees with cold hands is never a good recipe for accuracy. 

Anschutz 1761 silhouette 

 

IMG_20201205_140138.jpg

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16 minutes ago, ColinBR said:

Got this to have a go at some paper punching. 

Initial trials are proving fruitful with SK match. Though to be fair shooting at 100 yards in a breeze and 2 degrees with cold hands is never a good recipe for accuracy. 

Anschutz 1761 silhouette 

 

IMG_20201205_140138.jpg

Lovely looking set up, look forward to seeing the results.

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20 hours ago, Farmer rick said:

As mentioned in my posts before, I have a issue with eley subs going super sonic, so went out with a friend whilst zeroing the 222 and decided put some eley .22 through their cz452 whilst we were out for comparison, 55yrds low wind 5mph, 8deg c with interesting results:

my rifle - cz 457 mtr

test gun - cz 452 - same as you I believe @No i deer

both moderated etc...

all reports from the 452 where quiet and sub sonic.... 457 all loud and super sonic... tested with eley match also and the same acoustics were heard.

so I can only conclude that the match chamber is in-fact producing a higher pressure that a “standard” chamber and causing a increase in velocity. As mentioned before rws subs are absolutely fine, stay subsonic but not quite as good grouping as the eley subs.

eley subs:

as many have said they don’t shoot well in their guns...

cz 452 - dreadful, around 1.4” (could be barrel acclimatising)

cz457 mtr - great: around 0.3”

Eley match:

cz 452 - 0.5” (one flyer not counted benefit of the doubt as barrel acclimatising)

c457 - 0.4” (one pulled low)

Cci subs:

cz452 only - 0.7” but again a lot of swapping ammo around maybe not fair...

From this is can say that there is a significant different in the eley subs between the 452 & 457... which could be down to chambering....

But the match seem to perform well in both. 

 

 

It would have been interesting to have put them through the chrony. I think ignition is more of a factor here, between the 452 and the 457 rather than the chamber. About half of the potential accuracy with the .22lr seems to be attributed to the chamber/leade/lock-up/ignition. The shape, depth and position of the firing pin strike on the rim has a considerable influence in velocity.

The firing pin spring in the 452 is possibly 20 years old - If the bolt is removed for storage the spring is under full compression almost all of the time.
I have a lilja match barrel on my Sako Finnfire P94S but if I was thinking of fitting one to a CZ I would start with the 452 action rather than the later 455 series. The 452 has a proper locking lug, the 455+ only uses the bolt handle as a locking lug.

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I never take my bolts out only for cleaning lubing etc unless I go in home and not put rifles away strait away..

I take the bolt/bolts out and put them in my pocket or holster and when I put them away I decock them..

People have a tendency to forget the bolts when they go out shooting not being kept in the rifle..

Triggersqueezer  did that very thing this morning 🤪

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Well I have finally got round to having a play and continuing from yesterday’s interrupted session. 
was rather foggy so I had to change out the targets for something I could actually see. I had so 50 meter mc queen’s target I scanned a while back that I keep in the truck for general messing about. So all was good. Will post up result later. 
I shot 4 targets at 50m and 4 at 100m 

no excuses they are what they are 

 

2819E5F2-A9E8-4BEA-AA50-8F35F9804E68.jpeg

5073C2F0-EEE7-4C52-9F03-840042A8F89F.jpeg

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1 hour ago, 1066 said:

It would have been interesting to have put them through the chrony. I think ignition is more of a factor here, between the 452 and the 457 rather than the chamber. About half of the potential accuracy with the .22lr seems to be attributed to the chamber/leade/lock-up/ignition. The shape, depth and position of the firing pin strike on the rim has a considerable influence in velocity.

The firing pin spring in the 452 is possibly 20 years old - If the bolt is removed for storage the spring is under full compression almost all of the time.
I have a lilja match barrel on my Sako Finnfire P94S but if I was thinking of fitting one to a CZ I would start with the 452 action rather than the later 455 series. The 452 has a proper locking lug, the 455+ only uses the bolt handle as a locking lug.

This is interesting... so what actually happens with the ignition / strike to cause the variation? Also apparently the 457 spring is 30% weaker than the 455 to help with accuracy so the tech gumph says...

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1 hour ago, One on top of two said:

Well I have finally got round to having a play and continuing from yesterday’s interrupted session. 
was rather foggy so I had to change out the targets for something I could actually see. I had so 50 meter mc queen’s target I scanned a while back that I keep in the truck for general messing about. So all was good. Will post up result later. 
I shot 4 targets at 50m and 4 at 100m 

no excuses they are what they are 

 

2819E5F2-A9E8-4BEA-AA50-8F35F9804E68.jpeg

5073C2F0-EEE7-4C52-9F03-840042A8F89F.jpeg

Looking forward to seeing the results!

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17 minutes ago, Farmer rick said:

This is interesting... so what actually happens with the ignition / strike to cause the variation? Also apparently the 457 spring is 30% weaker than the 455 to help with accuracy so the tech gumph says...

Some while ago I asked Bill Calfee (via his website) why he didn't rate the Sako Finnfire action very highly as the basis for a custom benchrest rifle. The two main reasons he stated was the ignition and the fact it didn't have a screw on barrel. He went on to explain how very important every aspect of the ignition phase was to get consistent ignition, from the shape, where it strikes on the rim, depth of strike, the power,  rebound spring oscillation, spring pre-load, weight/friction of the firing pin etc.

Remember, we are talking about extreme accuracy here where every little detail make a difference - a bit like a F1 car or tuning a two stroke motorcycle engine - little bits all add up.

According to Calfee the ideal firing pin should be a chisel shape, striking just inside the rim with the face ground at a shallow angle so the inboard tip of the firing pin strikes the case first. This initial dent from the tip of the firing pin happens a millisec before ignition. This dent forms a ramp on the inside of the case and deflects the ignition flash along the length of powder resulting in a cleaner and more consistent burn.
 

(Bill Clafee built .22lr benchrest rifles have won more International, National and state records that all other .22lr benchrest rifle builders put together)

Just one thread from Rimfire benchrest forum.
Firing pin energy vs accuracy (benchrest.com)

 

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Will have a read!

34 minutes ago, 1066 said:

Some while ago I asked Bill Calfee (via his website) why he didn't rate the Sako Finnfire action very highly as the basis for a custom benchrest rifle. The two main reasons he stated was the ignition and the fact it didn't have a screw on barrel. He went on to explain how very important every aspect of the ignition phase was to get consistent ignition, from the shape, where it strikes on the rim, depth of strike, the power,  rebound spring oscillation, spring pre-load, weight/friction of the firing pin etc.

Remember, we are talking about extreme accuracy here where every little detail make a difference - a bit like a F1 car or tuning a two stroke motorcycle engine - little bits all add up.

According to Calfee the ideal firing pin should be a chisel shape, striking just inside the rim with the face ground at a shallow angle so the inboard tip of the firing pin strikes the case first. This initial dent from the tip of the firing pin happens a millisec before ignition. This dent forms a ramp on the inside of the case and deflects the ignition flash along the length of powder resulting in a cleaner and more consistent burn.
 

(Bill Clafee built .22lr benchrest rifles have won more International, National and state records that all other .22lr benchrest rifle builders put together)

Just one thread from Rimfire benchrest forum.
Firing pin energy vs accuracy (benchrest.com)

 

thanks for the info. I have seen so of the br shooters stateside modifying the shape / profile of the 457 to create a almost pyramid shape. I think all CZ have the rectangular one that hits / cuts right across the rim (photo attached) hence the USA guys modifying its. I’ll see if I can find the thread about it.

but would the ignition cause such a dramatic difference in speed, I did chrono some rounds a few weeks ago and sent the results to eley: both subs and match were well over the stated velocities with subs actually averaging faster than the match - 1096fps with highs of 1113, match averaged 1086.

mean averages for match are  1040-1085

subs - 1000-1040fps so hugely different.
 

image.jpg

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30 minutes ago, Farmer rick said:

Will have a read!

thanks for the info. I have seen so of the br shooters stateside modifying the shape / profile of the 457 to create a almost pyramid shape. I think all CZ have the rectangular one that hits / cuts right across the rim (photo attached) hence the USA guys modifying its. I’ll see if I can find the thread about it.

but would the ignition cause such a dramatic difference in speed, I did chrono some rounds a few weeks ago and sent the results to eley: both subs and match were well over the stated velocities with subs actually averaging faster than the match - 1096fps with highs of 1113, match averaged 1086.

mean averages for match are  1040-1085

subs - 1000-1040fps so hugely different.
 

image.jpg

When you look at those cases they all look evenly struck and all went bank - Under normal circumstances no one would give them a second thought.  If you think a little deeper and think how a rimfire case is formed - The case has been formed so already work hardened to a certain extent and the extreme edge, 10 thou thick is actually a solid bit of brass. Do we want to expend any available energy crushing a solid bit of brass. There's no priming compound in the extreme edge so a custom benchrest rifle could well have the face of the pin angled slightly to tend to squeeze the priming compound towards the outer edge then be ignited.
Take a look at the pictures half way down this page  - A new idea, a lot of work going on searching for more consistent rimfire ignition.

Sako Quad .22lr (takilta.fi)

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7 minutes ago, 1066 said:

When you look at those cases they all look evenly struck and all went bank - Under normal circumstances no one would give them a second thought.  If you think a little deeper and think how a rimfire case is formed - The case has been formed so already work hardened to a certain extent and the extreme edge, 10 thou thick is actually a solid bit of brass. Do we want to expend any available energy crushing a solid bit of brass. There's no priming compound in the extreme edge so a custom benchrest rifle could well have the face of the pin angled slightly to tend to squeeze the priming compound towards the outer edge then be ignited.
Take a look at the pictures half way down this page  - A new idea, a lot of work going on searching for more consistent rimfire ignition.

Sako Quad .22lr (takilta.fi)

Thanks for the article, here is what the USA guys are up to reproducing thier own pins in the cz https://www.rimfirecentral.com/forums/showthread.php?t=1162011&amp=1

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44 minutes ago, Farmer rick said:

Thanks for the article, here is what the USA guys are up to reproducing thier own pins in the cz https://www.rimfirecentral.com/forums/showthread.php?t=1162011&amp=1

Ahh yes, that's interesting. I got to say, the CZ striker is hardy a thing of beauty, if you were trying to design the perfect firing pin I don't think that's how it would look. There are arguments about whether the strike should be at 12 or 6 o'clock and whether the spring should go around the pin or the pin around the spring. There's no doubt an action with good ignition leads to more  consistent velocity which must pay dividends at longer ranges.
 

Even with good quality .22lr ammunition we regularly see a ES of 20-40fps - this, in percentage terms would equate to something like 100fps in a centrefire round. Careful centrefire hand loaders are now getting ES down in single figures.

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