serious mac1 BENCHREST shooter wanted

Frank,
These are my Numbers with the .22 barrel with 18.1 JSB's out of the tin.
My valve work and breech clean up with the .22 barrel now has JSB's 18.1 going around 900 before I couldn't get over 800.
From a 2,000 fill 1st 905 906 905 909 903 900 909 905 906 910 912 912 914 910 909 912 910 908 907 908 909 906 907 904 903 905 906 896 902 899 901 898 897 896 896 891 889 888 884 884 884 882 879 878 872 875 869 866 868 I stopped and the fill was at 1500.
I sent you a couple of emails with info from LD and Tim.
When I received the USED USFT the Swing Breech stop was bent so I was closing it by feel. I got the old pin out and put a end of a drill in. I see the Gen 2 has a bigger stop. Mine seems to be centered. I still havn't received a .20 barrel either from Tim or LW.
Thanks for your vice grip way of dumping air. I was wondering with your glued on barrel clamp and bottom plate. And inch lbs on the bolts, any air leaks?
Paul
 
Hi Paul and Hulk

Hulk thanks for your comeback and interest I welcome all knowledge and thanks Paul for the data. It seems for 25 shots you have about 11fps variation.
I think without looking I am running about 9fps. w/ my.177 My question still remains the same. What is concidered standard variation in FPS out of Tim's gun?
Tests confirm that higher than standard velocities within a given group produce elevated shots and visa versa. So it seems reasonable that the less the variation in velocity the smaller the groups. Astute shooters know a untuned barrel or bad bedding can also exibit vertical groups

Now, without seeming stupid which trust me I can qualify for in an instant, where would the air be leaking from using my bedding method? Do you know something I do not?...... Enlighten me here my friend.

I also find and maybe you guys can add something to this, if I run a wet patch thru my bore with lube prior to shooting my initial shots seem to level out velocity wise real fast. This lets me get real good sighters fast and jump down on the record with lots of spare time.

Now something from my many years of rimfire ammunition testing and competition that you may find interesting particularly those that think a wire brush removes lead........it does not! It just smooths it over and spreads it out. Bore scopes have confirmed this for years. Second there is not a benchrest bbl maker out there that will advocate using steel wool in a bbl.for anything unless you want it to stop shooting. We learned from looking at many thousands of them that it rounds the sharp edges of the lands off decreasing extreme accuracy. AND rimfire lands are much deeper than airgun. You might wish to remember you are looking at only maybe 25 RC tops here. I think I have measured a few airgun bbls at 18RC This is soft steel. But do what you think best.
Paul, will you call me some evening 903-734-3667 I would like to pick your brain. Use to live in your state.
Thanks Frank
 
My thoughts

1800 psi is the recommended max working pressure of the USFT rifle, no need to go higher. It says 1800psi on the barrel block. I can get up to 925fps from 18.1gr .22 pellets using only 1650 psi.

And ... please do not share info you see on pages of my USFT club here.
 
therealld,
Larry maybe you could post a link to your forum? I don't have it on my blackberry or I would.

Frank I will call you after the Hollidays.

Paul
 
air strippers

SOME THOUGHTS TO PONDER: I see everyone is all excited about the air stripper craze and have to admit I even for curiosity's sake had a hard look at them. I am sure that some folks swear by them but I offer these thoughts for concideration.
It is a fact that any alteration to a stock barrel will change accuracy be it improved or make it worse. Barrel tuners in whatever shape or form have shown to MOSTLY enhance accuracy for years. They do nothing more than through weight distribution change the WAVE harmonics within the piece of steel we call a barrel. Adding one to a barrel immediatly reveals two things, point of impact change and group size.The optimum goal with any tuner is to make the muzzle flip start and stop in the same place for each shot resulting in consistency.
Reverse taper rimfire barrels, short or long barrels are all are tuners in some form. Barrels rotated within the breech block to enhance accuracy attempt to do the same thing but to a lesser degree. It just simply changes harmonics. Even clamping pressure will change harmonics. Bottom line being you are just looking to create a "Happy Barrel"

Now with that said, why would one not REASONABLY assume that the addition of the air stripper, which is weight would TOO not alter barrel harmonics?........ It will!
My real question is this, How do you know the airstripper is doing what it's design sez it is doing (chaneling air away from the pellet base) or has it become a rough tuner of sorts...... or both?
If Air Arms or anyone is working on this project why have we not seen sequenial photos of the air movement as a pellet goes through the thing as well as IMPROVED targets? These are reasonable questions you people should be asking. Would this not be a real plus to us airgunners if in fact it does provide for a more stable pellet? That answer is yes! Even if it does what they claim with the air, the BOTTOM LINE is still what shows up on your TARGET. Are the groups REALLY smaller?
I am just asking questions here.....Show me the Beef!

For those of you that care to remember Moly Coating bullets was once touted as the greatest thing sence sliced bread in the extreme accuracy camp as was coon tails, chrome and hubcaps that made your car go faster. We all know better now as did friend Harold Vaughn, author of
(Rifle Accuracy Facts) from the very beginning.
Do your own testing in the best conditions you can find and fully understand what you are doing.
The road to the Grail is long and hard.
 
air strippers

I must have been sleeping when the subject of the "airstripper" came up. Can someone post a picture of this animal and where a body can get one. I have a thing on the end of my USFT barrel that looks like a muzzle brake. Could this be the same thing or is it like the noodle that James Pappas makes?
HELP
Larry
 
More

Some believe they work. Whether it is due to a change in barrel harmonics or a change in air turbulance, difficult to prove. Designs typically have a cone insert and a body with windows to release air. Cones are typically adjustable as to the distance between the cone entrance and the crown of the barrel. Some thoughts are that two (2) pellets length is a good starting point for this distance. The body will usually have a shoulder to index the barrel to the proper position. Seems to be more accepted as a concept in the UK and Europe. This is likely due to the longer legacy of air rifles on that side of the pond. The gentleman who owns the website for this gallery shows slight differences in design by air rifle model but if it fits properly on your barrel, everything should work or not, depending on your opinion.
 
How do I know if my airstripper works

First off, an air STRIPPER is intended t improve accuracy by stripping air off of the pellet as its leaving them muzzle. Its known by many that the air exiting can, and does get out ahead of the pellet when fired from powerful co2 and compressed air guns, as its going faster than the pellet. The fast moving air creates turbulance, and also tends to blow the pellet in different directions, causing or extending the unstble perios od its flight.

A BRAKE is intended to cut upward and rearward movement, allowing better follow-through, and reducing recoil. Many, if not most brakes also work as effective air strippers.

I designed my "tee-brake" to perform the function of a brake AND a stripper, and, bring "lucky" enough to have a 51 yard underground tunnel for accuracy testing, I was able to do the development testing in the tunnel. By testing accuracy and precision with and without the device, I was able to determine the stripper effect DOES improve groups by a small, but measurable amount in most cases. I deliberately kept the weight and length low to minimize its effect on tuning, because I found with my gun, this worked well, and helped avoid snagging the barrel on something while walking around with it.

I found my double chamber design had a "sweet spot" that worked for most guns I tested, and ended up adding a small shoulder inside for it to butt up against the muzzle so I didn't need to trial and error the placement anymore.

I once tested the effect of drastically reducing the "stripper" effect by boring the hole quite large in the unit to negate the stripping. Groups increased around 1/32" at 51yds. (my tunnel isnt set up for different target distances.)
 
Last edited by a moderator:
Here it is Paul: http://forums.delphiforums.com/bulldurham/messages

Paul Bendix said:
therealld,
Larry maybe you could post a link to your forum? I don't have it on my blackberry or I would.

Frank I will call you after the Hollidays.

Paul
Click to expand...
-------------------

Its a bit involved to see the USFT folder, since you need to belong to the USFT club before its visible.

A sort of quirky Forum, since the search function is near useless unless you pay for an upgraded Delphi membership, but its possible to page back thru the posts if you study up some, and back when I started, it was all there was that I knew of, plus it keeps the guys with shallow interests away.
 
Therealld

Thereald, great answer on the stripper question. This is the type of info that needs to be out there. Thank you for the clarification and your experiences. Great great stuff!

A brake came with Tim's gun and once it was shooting well I put the brake on and shot 5 groups in dead air in the tube.( Just because you have a tube DOES NOT MEAN YOU HAVE PERFECT AIR. anyone that has one knows this to be true) and the agg was larger than the gun had been shooting.
At face value one would say that the brake was NOT WORKING but that is an incorrect statement.This is what often happens when people test and are not fully aware of what is REALLY going on. What actually happened is the tune on the gun changed with the addition of the brake and it needed to re tuned to the brake..... TO MAKE THE TEST VALID.
Then and only then could they be compared to make an accurate assesment on it's affect to accuracy. The findings were that on my gun I found no improved accuracy.
In all fairness I have been beat by guys using them.
Test for yourself and make up your own mind. I don't care what anyone sez or how it's advertized. If done correctly it's only what shows up on the target that is the truth.

For what it's worth:
I checked with the serious rimfire benchrest boys this morning as there is a similar toy on the market there also. There findings are that they could not confirm it improved accuracy and using it. It also meant(LIKE US) that you had to re tune your gun to make it shoot because of the added weight.

Frank
 
Larry,
Thanks for the info to your forum.

Frank, I had mine apart today so took a picture. Larry is the one to ask questions you have about your USFT as he is the one that started it all. I think he is still shooting Simple Simon the first one he designed and built.

IMGP0251.jpg


Paul
 
retune with brake

When I add the brake, it normally works ok with the standard barrel length and power level of the gun (I always try before and after), but for some, I have used a mid-barrel tuner/damper as well to try to get the last little bit of accuracy.

I have noticed some barrels are not bored concentric, and its important to try rotating the barrels in different positions to find the best .... I normally try them every ninety degrees to find what works better. The barrel will flex differently in different orientations, and I prefer a round, or slightly oval group with the oval up and down rather than sideways.

"Clocking" the barrel like this and tuning with the weight sometimes gets rid of the dreaded "double group" syndrome.

Yes, to get "still" air is a real challenge, but its good enough in mine ... I (fortunately) have some cobwebs I can see hanging near the end of my tunnel, and use them as an indicator of air movement. Anyhow, a very small amount of steady movement seems better than dead air to me.

The USFT was designed for FT and careful evaluation showed a gun that can consistently put em into a nickel sized hole at over fifty yards can win any match, so I'm used to tuning until this level of consistency is met. It isnt productive to try to obtain the absolute tightest groups with these guns in the tunnel, since it doesnt truly relate directly to field use anyhow.

As to benchrest, well, I didn't like the game most of you guys shoot, since it takes so much emphasis away from the shooter, esp if fired indoors, so we shoot at fifty yards in the wind out here. It does take a fair amount of accuracy, but the main hurdle s wind doping. Almost any decently accurate and powerful sporter can do well at my matches if the owner dopes wind well, but like all benchresters, we are never truly happy with any barrel unless we are always winning.
 
LD,

What you call "clocking" is exactly what many others call barrel indexing. Credit should go to Mike Ross for testing the concept with smallbore competitors and Bill Myers/Gene Beggs for developing a bushing for rimfire benchrest use. While they are hesitant to admit it, Anschutz and FWB may have been using barrel indexing for decades to hand select barrels.

Since the USFT was and is a purpose built FT rifle, what changes would you make for a purpose built benchrest rifle? Thanks.
 
great dialog

LD, you are right on the bbl rotation and mid bbl tuners. Great to have your imput on these things. Us guys trying to figure your guns out are thankful to you.
As for the benchrest crowd which I have been a part of for 40 plus years I would like to offer a bit in our defense. You are correct it does take a lot the human error out that is exactly what the sport is intended to do. We want to prove the gun and components not the shooter. The shooter is the least effective component in the matrix. It is just another shooting discipline used to put the best equipment in the hands of a shooter.
Tunnel shooting as you are aware makes it possible to tweak the nth degree out of a gun or component that can never be done outside. It however is not without it's own problems such as optical variations or crosshair floating that appear when bottom tube air meets cooler top air. A variation of 3 degrees will induce this condition. We saw it a lot testing rail guns and too it is almost always the area we are attempting to shoot through. It is not rocket science reasoning to understand that well tuned gun in a tube producing small groups when taken outside has a bunch of safety factor built in for misread wind conditions. Why would you want to enter a race with a Pinto when you could be driving a Ferrari?
 
Well, the idea of indexing didt take a lot to figure out

I was doing it back in the eigthties on old Daystate air rifles ... but I guess like rimfires, its a pain to accomplish unless the gun is a natural for it. The Daystates and later Ar6 rifles i was working on were NOT naturals, being screwed in and needing to be faced off to exact length every time, but I still used to do it to try to get the best result I could.

When I designed my own gun (I designed it in the late nineties), I made sure changing or resetting the barrel wouldn't be a big pain.

As to a dedicated BR gun, well, I'm not so sure its worth the effort, being its such a backwter sport, and the probable returns in better shooting would be so miniscule with just an improved or dedicated gun design.

See, to me, the main issue is STILL the ammo, and I think the barrel/ammo combinations today prolly cannot be improved more than a few percent, with respect to optimizing em to work better. Barrels are also a pain in that only a few e "good enough", but the ammo is more problematic than the barrels, since if you know how to work over a barrel, some that show promise can be made to shoot better.

I feel stuff like rests, triggers, and stock design, are minor details, and that there is wide latitude there ... a great barrel can make about any brand gun shoot decent, but not vice-versa though. I simply bolt a 3" wide and flat aluminum rail to the forend bracket and a 1" aluminum rod under the buttplate to convert my FT, though for a couple guys, I did rework the trigger to a little under three oz for em too. The .177 works ok, though when the wind is up, the heavier stuff allows for faster shooting, since you don't need to wait for your flag conditions so long.

I feel in order to have BREAKTHRU improvement, better pellets or bullets must be readily available, at which point, better barrels can be made to work with those projectiles. But, the game you lot are playing already has rules to discourage this sort of breakthru, so there it is.

As to making incremental gains with USFT I am now using for benchrest, I have gone with the trend of faster pellets with better BC than is normally used for FT .. such as the 5mm Crosman and JSB pellets, as well as the .22 cal 18 gr and 21 gr pellets, and I'm even toying with some 30gr stuff I have from earlier days ... which were "backdoored out of CC! from their .22 short line.

Our club shoot has a rule that the gun isnt to be recharged during a leg (mostly for safety, but also to kybosh the ideer of guns tethered a remote tank on the floor, which I see as an abomination), so we need to be able to fire 30 record and a few sighters on a charge ... I got Tm to make up some special longer reservoir tubes to allow high power and still get enough shots per charge. The big tube is useful for .22 cal, not so much for 5mm or .177.
 
You mention about refilling during a realay/detail or not being allowed to.

I have seen chrono strings on here that to my mind aren't that good if we are trying to get best accuracy out of these rigs.

In the UK we shoot 12ft/lb maximum and most shoot .177 most would be looking for + or - 5fps through the part of the fill to be used on an unregged gun, a properly set up S400 Classic would give a good 50 shots well within this range usually better than a regged gun but obviously not as many usable shots. Also having the benefit of higher pressure air over a regged gun as well.

Again going back to filling I find I have to shoot my Daystate Mk3 RT from 140bar down to 100 this gives me 50 shots ish but mainly by running so low it seems to take stress off all the components and also is the other side of a zero shift if it is filled up to 200bar plus. Are you all filling to the maximum and then shooting down through the whole fill to achieve your required shots at 20ft/lb?

I also find that if the gun is left for a few days to get cold it is very accurate but as it needs to be filled between cards that accuracy is of no benefit as once filled and warm things move that said if I put it away and refill before shooting then everything is fine.

I also have found and if you look at the UKBR22 scores for the last few seasons that the scores in the Unlimited and the Hunter classes are very similar tending to show that the weight and flat forend advantages that most percieve, according to the results are in fact lacking to the extent that many of us have ditched plates and rests and gone to bipods(been banned for the World rules) put our factory stocks back on and our scores have both gone up and gained a higher level of consistency. Also most who have elevated themselves away from the S400 and outfitted themselves with Race guns like Steyers, Feinwerkbaus, EV2s and the like have invariably returned to the simple and agricultural S400 as it does what it says on the tin.

My main problem seems to be poor technique navigating around those 25 bulls as the gun with a bare barrel, no shroud no MFC airstripper or presilencer shoots five shot groups that a single pellet will not pass through yet introduce a bit of head movement cheek weld stock stress etc. and you have a nine.

Like most things human error probably plays a bigger part than most will admit.

Andy
 
Andy.
Fitted the adjustable to the MPR. The POI dropped on the vertical by 12mm.
Wound the cone all the way home, shooting free-hand indoors, rezeroed and experienced the normal pattern of rotation expected.
6mm adjustment took the groups sub 6mm, another 0.25mm saw the rotation lost and pellet on pellet, largest hole diameter 5mm.
Guinea-pigged Graham on a rifle he's never shot before and he slotted 8 into the same hole ......... freehand!!
Evidently he's ordered one in brass and gone shopping at Air Arms.
:)
 
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