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  #961  
Old 12-01-2019, 11:47 AM
jaia
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Top, thanks for the confirmation I'm thinking in the right direction.

David, how would you ensure it wasn't variations in the ammo, not barrel length?
Coefficient of friction is going to apply no matter barrel length.
Chamber pressure will vary depending on powder and primer chemistry and amount.
Length of barrel does affect top speed of the bullet.
But I think MV spread is more directly related to cartridge production variations.
Not like rimfire ammo quality is a constant.

Last edited by jaia; 12-01-2019 at 11:51 AM.
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  #962  
Old 12-01-2019, 01:56 PM
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Dave, hope this helps some but it's not always 100% true. Both my Freedom Arms 10" and Anschutz Exemplar 10" barreled pistols use the same settings as most of my 28" barreled older target rifles. My shorter barreled Russian rimfires are faster and use slightly less elevation to hit the same targets from 25 yards to 197 yards.

The exceptation to this is my 28" Remington 40XB which is my fastest gun and uses less elevation than any of my others. Another guy we shot with also has a Remington 40XB and is also a fast gun with settings nearly identical to mine.

This is shooting midpriced ammo such as SK and Wolf which we all use in our guns for my matches. I just got a case of SK Biathalon but haven't tried in the various guns to compare settings versus barrel length.

Think the 10" barrels are still accelerating and the 28" are being slowed slightly. On a good day both short and long will be competitive although the shorter barrels are WAY more sensitive to shooter input with the Freedom being the most picky.

I don't chronograph my shots but use my targets at 197 and beyond to gauge accuracy and how a particular ammo will perform. I accept anything that will consistently stay on my clay pigeon size target at 195 yards good enough for my matches. In some guns I get that with the cheap $2.06 Geco rifle stuff.

These rimfires are sensitive to so many things but I've seen so many competitors at my matches going from being happy to hit a few of my smaller plates to now nearly cleaning my course. I limit my ammo to no more than $8.00/50 so I really think we have critiqued and become so sensitive to what makes the guns shoot AND paying attention to what Mother Nature is telling us we are hitting more and really small targets.

A few years ago we were ridiculed when we told others how far we were shooting but now ELR has become the fad and everyone is giving it a go.

Hope this helps some.

Topstrap

Last edited by Topstrap44; 12-01-2019 at 03:15 PM.
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  #963  
Old 12-01-2019, 02:32 PM
David Valdina
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Follow up on proposed ammo/barrel length test.

If the ammo used is the same, and enough shots are taken, the variable in the standard deviation should be due to barrel length.

My thinking goes along these lines: Commonly held "knowledge" is that 16 inches gives maximum velocity for a standard .22 rimfire cartridge. So that is assuming all of the expansion from the powder has taken place. Beyond that, barrel friction will slow the bullet. And earlier, the powder is still burning. I am thinking it may be more difficult to burn the same partial amount of powder for consistent velocities in a very short barrel. And a longer barrel, although maybe slower, may be more consistent.

This is the problem with sitting around and just thinking.

I also shoot old Wolf Match Extra and SK Rifle Match for almost all of my bench shooting.
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  #964  
Old 12-01-2019, 06:17 PM
Arrowhead
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The rest in the second picture is interesting. Is it a commercially made rest or a custom made one?
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  #965  
Old 12-01-2019, 06:43 PM
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In handguns, just as rifles, variations in 'hold' result in spread, it is just magnified with hanguns. It is so predictable that there is an 'error wheel' showing poi changes due to the various holding errors. I havent seen one for rifles, wish I would.
Anyhoo, I figured out for me that to get my primary grip on the gun and Not let go with that hand helped a lot, I do as much other stuff as possible with the other hand if needed.
It is really no big mystery, just do everything exactly the same every time and things tighten up nicely.
Lol......
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  #966  
Old 12-01-2019, 08:19 PM
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I made it. I first made the 40moa mount and planned for a way to add a bi-pod shelf. The brackets straddle the action and the shelf attaches it it.

Still wanted to experiment a bit further to try and eliminate some of the shooter I put with a rear grip/bag hold.

It does really work well but other than using it for our local lo Grange rimfire matches or stretching it out it's pretty impractical. It'll give the rifle guys at the matches run for their money though.

I'll try to add more pictures of various areas tomorrow when I'm on the computer.

Topstrap
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  #967  
Old 12-03-2019, 09:57 AM
Arrowhead
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Thanks for the reply and I'm looking forward to more pictures. I would like something for shooting steel plates at around 100 yards and have been scratching my head about designs. I haven't seen anything commercial so far that has inspired me to build an improved version and certainly nothing I would want to purchase. I'm always interested in what others have dreamed up and built that pertains to the shooting sports.
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  #968  
Old 12-03-2019, 05:47 PM
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I guess I should say this isn't a "rest" but is all integrated together as a single unit that is able to come apart to shoot with a wide range of variables.











I really like the Henry Remple front rest for most of my guns including the pistols, absolutely Rock solid and easily adjustable. I don't allow the fancy benchrest type rests for my matches and use Harris or Atlas for PRS and some of our other style matches.



Topstrap

Last edited by Topstrap44; 12-03-2019 at 05:50 PM.
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  #969  
Old 12-04-2019, 12:24 PM
Arrowhead
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You have nice equipment. I use a front rest that I can level because of the sad shape our tables are in. There has been talk this year about replacing them. I'll believe it when I see it.

I built this a few years ago and it works quite wll in my opinion. It weights a little over 17 1/2 pounds so it stays where it is placed.

https://i.imgur.com/twdXnht.jpg

I have also made a pistol rest top for it that works fairly well but don't have a picture

Last edited by Arrowhead; 12-09-2019 at 09:35 AM.
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  #970  
Old 12-05-2019, 01:06 PM
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Quote:
Originally Posted by Arrowhead View Post
I built this a few years ago and it works quite well in my opinion. It weights a little over 17 1/2 pounds so it stays where it is placed.

https://i.imgur.com/twdXnht.jpg

I have also made a pistol rest top for it that works fairly well but don't have a picture
That Sir, is a fine piece of kit! Built like a tank
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  #971  
Old 12-08-2019, 02:25 PM
jaia
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Prime Semi-auto 40 grain 22lr rated 1148 fps

Ruag/RWS headstamp



Ruag/RWS date code on the end flap



CZ 455 Varmint, Lilja barrel, Sinclair bipod



First 50



Second 50




No failure to fires.
Cartridge inspection showed very few dents or dings.
Some excess lubricant congealed as a flat spot on the bullet tips.


So since it's for a semi-auto, out comes the Buckmark Silhouette



Two wood blocks under the towel, much firmer setup.

First 50 I was all over the place adjusting to the mv and wind.
Adjusted the turrets to fit the ammo and conditions.



Second 50 much more consistent



With the SE headwind coming from my 2 o'clock
the turbulence coming over the berm caused some of the vertical,
the rest is on me. Headwinds and tailwinds kick my adze, every time.
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  #972  
Old 12-08-2019, 04:00 PM
BillOH
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This is 50 at 140 yards. Vudoo, SK Biathlon, bench with bi pod and rear bag. I was practicing running the bolt and shooting as quickly as I could.

IMG_4509.jpg
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  #973  
Old 12-08-2019, 05:17 PM
simpletom
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Nice work!
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  #974  
Old 12-17-2019, 05:16 PM
jaia
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Armscor 40 grain Standard Velocity rated 1135 fps
Made in the Philippines.



CZ 455 Varmint, Lilja barrel, Sinclair bipod




Rated 1135 fps? Standard Velocity is supposed to be 1070 fps.
Visual inspection of the cartridges shows dents and dings and scratches and tool marks
along with irregular spacing of the drive bands and varied bullet seating.


Chambering showed differences in brass dimensions also.
Some fit snugly, others wobbled around in the chamber.

With those problems already apparent, I expected strays and got them.


Sent the first 5 to adjust the scope, then 45 on target.
ES almost 100 fps, strays spinning off line confirming visible ammo quality.
Three fail to fires that went bang on the second try after extracting, rotating and rechambering.



The next box had the same problems.
Only one fail to fire this run.



The last box had similar results with another fail to fire.



Packed loose like bulk ammo, looks like bulk ammo, results are typical of bulk ammo.
What's that saying about ducks?

quack, quack

Last edited by jaia; 12-17-2019 at 05:49 PM.
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  #975  
Old 12-17-2019, 05:37 PM
flangster

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Consistent with my experience at 50 yards with this ammo. . .
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