22LR Bench Rest Shooting

[rick137]

In the Houston Warehouse Experiments the rifles were allowed to free recoil since free recoil was considered more consistent than trying to apply the exact shoulder force for every shot.

I assume a shoulder force is used in some bench rest shooting to prevent the rifle from recoiling off its support.

However, for 22LR bench rest shooting I assume the recoil would not be sufficient to de-support the rifle, at least if rifle weighed, say 7 or more pounds.

Thus, would not accuracy testing of 22LR ammunition be best done with free recoil?

 

[Starbuck]

Accuracy testing of .22LR is best done with the barreled action clamped in a vise - at least this is how it is done at the Lapua Testing Center in Mesa, AZ.

 

[...]

Accuracy testing of .22LR is best done with the barreled action clamped in a vise - at least this is how it is done at the Lapua Testing Center in Mesa, AZ.

That is also how the Eley test center does their testing.

 

[rick137]

Learn something new about firearms everyday. How different are the barrel harmonics in free recoil and clamped? If the barreled action is clamped so the barrel is free floating then the barrel harmonics might be close, very close, to free recoil.

I presume one advantage of clamping is the rifle is always in battery.

Most interesting. Many thanks, Gents, for the intel.

 

[Kickin45]

Interesting. So I’m assuming that’s how all mnfrs test their ammo? If 22lr is done that way, are large caliber done that way as well?

 

[TimK]

BTW, the fixture Eley uses allows the rifle to move to the rear in recoil. I watched my rifle get tested, and I thought the amount of rifle movement looked about right compared to shooting normally. If anything, the fixture probably allowed it to move a little more than it does when I'm on it.

 

[...]

BTW, the fixture Eley uses allows the rifle to move to the rear in recoil. I watched my rifle get tested, and I thought the amount of rifle movement looked about right compared to shooting normally. If anything, the fixture probably allowed it to move a little more than it does when I'm on it.

when did you have your rifle tested?

i built a private test tunnel about 5 yrs ago that mimicked the Eley test centers rigging......from the info i had they were using a fixed clamp mounted to a steel table that was anchored in sand to dampen vibration.

 

[JG26_Irish]

How different are the barrel harmonics in free recoil and clamped? If the barreled action is clamped so the barrel is free floating then the barrel harmonics might be close, very close, to free recoil.

I presume one advantage of clamping is the rifle is always in battery.

Ammo testing is done with a clamped action because it is faster that way and the rifle is always consistently aimed and the same spot. The goal is to find the best lot relative to the others not necessarily find the smallest possible group. My point is that rigidly clamping an action into a fixed fixture will alter to some degree the vibrations and harmonics induced into the bbl as the bullet travels down its length. It may or may not produce the best possible group other than providing perfectly consistent POA for every shot. There is a reason that all championship benchrest shooters allow their rimfire rifles to "Free-Recoil" as opposed to clamping them into a fixed aiming fixture. Even doing what they do, I have likened benchrest shooting to being more like rimfire artillery practice than rifle marksmanship, lol. Whether clamping or free recoil is better is likely going to depend a lot on each rifle and its specific harmonic features. I like what Eley is doing allowing the fixture to move with the recoil and then return to its position. Again, like an artillery piece.

I know this changing the harmonics of a gun can greatly improve or hurt its inherent accuracy. I took off the receiver mounted modern 8-24x optic on my Winchester model 52 and installed a vintage long tube bbl mounted 6-24x optic. This single change transformed my nice old decent shooting rfile from printing sub MOA at 50y (1/2" groups and sometimes less, usually running in the 0.700 to 0.433" range for five shots) to printing sub 1/2" at the same distance with scary consistency. I think the bbl mounted optic bridged a long span of the bbl length and made it effectively more rigid just like a simple truss on a highway bridge. It was amazing.

0.268" / 0.512 moa (JG26Irish- Winchester Mod 52 9/13/15) this was with the bbl mounted optic.

Irish

 

[rick137]

Irish:

Do I detect some hint of condescension for bench rest shooting? If your game is bench rest shooting, why go half-way? Buy or make a rail gun. Mount it on wheels and you do have a miniature artillery piece. That to go along with your 6 foot, 40 lbs, $7/round ELD rig.

Do not competition rimfire bench rest shooters use a turner weight at end of barrel? Your scope is a barrel tuner. When a shot is fired, after a short time for the energy to travel, every part of the rifle vibrates. The magnitude of each harmonic in each part of the rifle is time dependent. Presumably the most important vibrations are those of the barrel. But the barrel is clamped into the receiver and the receiver to the stock/chassis and both these parts are also vibrating.

In the photo of your trusty rifle the rear of the pistol grip would prevent the rifle from free recoil. Do you actually do bench resting in that configuration? Also what is the outer diameter of the inner green annulus since I am not familiar with USBR targets. I would guess 1/2".

RS

 

[Tiger_Shilone]

I have likened benchrest shooting to being more like rimfire artillery practice than rifle marksmanship, lol. Whether clamping or free recoil is better is likely going to depend a lot on each rifle and its specific harmonic features. I like what Eley is doing allowing the fixture to move with the recoil and then return to its position. Again, like an artillery piece.

That is actually a pretty accurate assessment of the sport. Your hurdles to overcome are wind conditions and ammo consistency. I started benchrest to get my PRS style guns as accurate as possible without me as a factor, I knew I had no chance of winning the benchrest match but I had my PRS rifles sorted out good enough to win in other events. Now, I've kind of gone off the deep end and getting more interested in winning a match (hasn't happened yet, but getting closer)

Martini International MKII in one piece rest for pic reference:

 

[rick137]

An awesome support. From your comments the rifle must be competitive with a modern Anschutz match/target rifle or a purpose built match rifle.

With 22LR what is your procedure for buying ammunition with the best consistency? And how do you measure consistency?

 

[Tiger_Shilone]

Nah, I took a chance buying this Martini earlier this year and it didn't pan out well, barrel is corroded so badly internally that it's probably missing 2-4" of internal rifling when I finally inspected it with a bore-scope. Had a bad feeling about it when I first got it and it took over 60 patches before the patches started turning from black to lighter grey, lol. Looks like molten lava flowed down parts of it, but that is the chance of a 60+ year old gun coming from Britain's humid weather. Looking for a smith to either reline or re-barrel it now, kind of disappointed and amazed at the same time at this rifle as it groups pretty much .650-.800" at 50 even with all the rifling damage. Kind of heartbreaking as the barrel has some really cool proof marks

As to consistency, an indoor 50 yard range would be best with a rest set-up. Test lots of 1 or 2 boxes across 5-10 lots is the best testing I've done, but that gets real old real fast if you don't have your own indoor range as rental fees add up. This last year I just said screw it, and bought an untested case of Lapua Center-X from online and have been pretty lucky so far.

You are not competitive in benchrest unless your rifle is punching .300" or better for groups at 50 without wind. The wind is a big factor here in Colorado, it never stops. Range record is held by Lones Wigger and that is a 2350 out of 2500 possible (25 bull targets per card with up to 100 points per bull). He said "it isn't that Colorado doesn't have compeitive shooters, it just that the wind never stops blowing here." Some of the guys I shoot with have as much into their rifles as some of the guys at this site with their precision ELR rigs.

 

[TimK]

when did you have your rifle tested?

A year or so ago. They come to the Olympic Training Center here in Colorado Springs every year and I had them lot test for Edge in my 40X.

 

[Dank27]

Nice read

 

[Tiger_Shilone]

Re-reading the OP original post, if you look at the picture of my rest and Martini, you will see a green bungee cord that runs from the front rest post area around the back of the plate that is bolted on the bottom of the fore-end. This is what allows the rifle recoil and keeps the rifle from jumping out of the rest. The front head has roller bearings for the alum plate to roll on and the rear rest is a teflon roller where the buttstock extension has .75" rod bolted to it and it rolls freely there as well. The bungee returns the rifle into battery against the front upright post. This is a free recoil setup.

Most BR guys use a bungee or surgical rubber tube assemby tied to the front of the trigger guard to the front post of the rest for battery return. I doubt that I get an inch of movement from the .22 rifles. I designed this rest with a cut-out in the center to accomodate larger calibers with long magazines. the 6.5cr moves a good 3+ inches with the small bungee, I use larger bungees for larger calibers.