Sumo for the open class

C

csdilligaf

New member
Got an itching to get this ready for Rick Ing. to shoot at the east coast shoot in August. Its my Sumo action for the open class. Polished Hardend Stainless side lever with thru the bolt airflow with no probe. You can index the .875 dia Benchmark 3 groove barrel, Will take the Dawson Triggers and has a 1.5" titanium tube that will be 24" long with a Dan Brown regulator. I have to inlet the stock yet and finish the valve and then it will be off for Rick play with. I dont even know what power he want to get but this thing can really push a heavy pellet. In testing I got 65 ftlbs in .25 cal with a 18" barrel. For this one I reduced the transfer port size but it should still make between 25-55 ftlbs with the right tune no problem.
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Hi Chip I am looking forward to working with it . I well be testing 35 ftlbs. for open and 50 ftlbs +/- for unlimited . It looks like it wood be nice for my dream long range varmint rifle .30gr-50gr pellets or bullets .and 100yd +++ It looks over the top . Rick
 
OMG - I'm in love. Problem is, I'm going to have to shoot against that thing, and maybe two of them once Todd gets done. Guess the trick will be to stay down in the 20fpe and under Classes... that is right up until Rick decides to play with de-tuning it even further.

Chip, in my opinion the polished stainless is great and will make the gun look unbelievably sensational! Drop it into a nicely finished dark walnut stock, or, better yet, a black anodized Aluminum thing of beauty, mount a silver or black 10-50X scope with polished SS rings on top, and with the two polished tubes sticking out the front it will be good-to-go. It's like with a black pick-up, you just can't add enough chrome to bling it up.

I'm only glad that I insisted so much we include the 25's in the Unlimited Class, and this is exactly why I did. By leaving the door open with the extra caliber allowed something like this to come through it. I doubt very much that we would have ever seen a gun this up-scaled if the limit had been left at .22. I mean, just look at the barrel hold-down pins - all 4 of them. A true thing of beauty, that's for sure. And who knows where this will take us once the gun has been completed. 50Y Competitions? 100Y? Go for it!

And I can't even begin to image what it will be like once tuned down to be a .22 cal. Open Class, or even 20fpe Class gun. Yes, we do have a winner!

I'm very interested, but I may never be able to afford one - at least until I get creative. Know anybody who would like to buy a couple of .22 rimfire bench guns?

Good job Chip, and thank you!

Dave Shattuck
 
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It's getting better all the time. Not to get too far over-the-top here, but my choice of stocks for my Theoben was a Black - Gray laminate, so at least we're on the right page when it comes to looking good and keeping everything matched in my gun case. :cool:
 
Wow that thing looks awesome! I love the polished stainless! Hope I get to see it when it makes its way out East!
 
OK, I know next to nothing about air rifles. How accurate is something like this? Is 1/4moa aggregate score repeatably achievable?
 
alinwa said:
OK, I know next to nothing about air rifles. How accurate is something like this? Is 1/4moa aggregate score repeatably achievable?
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We will have to see just how accurate and consistantly accurate these new class of airguns can be. The open and unlimited class is still just starting but it does show promise. I have never built one to this level before so I am on edge to see what Rick can do with it.

and the stock is the standard Richards microfit bench rest stock and I inletted it. Needs some finish work but it should get things started.
 
How accurate ??? My hope is I can shoot the heaviest pellets ( 25gr - 30gr+ ) I can at 850 --1000 ft/se . I may have to go to cast bullets . I hope to shoot little one howl groups at 50 yd. .250" well not be good for bench rest . We well see . I am sure I well have fun and be frustrated at the same time .
 
Gotta love the big ass barrel:cool: I've held it and operated the side cocking mechanism--it's better than anything that I've ever used.
 
Sometimes you can tell a winner before ever touching it, and this one is absolutely the biggest winner I've ever anticipated seeing. As I said to Chip, if there is going to be any weak point to the gun, the biggest question in my mind is not about the action, but instead the barrel since that was not made as a dedicated airgun barrel, and/or whether it should be a 3 or 4-Groove. But, even with that, a little tweaking here, and adjusting there, and I'll bet even the prototypes are about to take us to where no mere mortal has ever gone before. Shear perfection, and once tamed a true Class leader for all the rest to fall in behind! You can just tell! Everything about what is being presented here is just right!

Dave
 
That rifle looks amazing!!! where can one get a 1.5" Ti tube w/reg? I've read very little about it from Mr. Dawson over on the Airgun Advice forum. What is the cc's of air a 24" tube will have? and who sells them??
 
I have been making the titanium tubes and end pieces and Dan Brown fits his reg into it. I am working with Gordon and Dan to take them over since Dan does such great regs and Gordon will need a supply of them for all the guns he is doing. I have sent some to Maxbar inc for destructive testing and they burst at 17,448 psi. I'd say that is a good safety factor. I like safe, safe is my friend.
 
Chip,

With what you just said you have answered one of my concerns, and that was just how much pressure could safely be charged into the tubes where your actions are designed to shoot .25 caliber as well? If they were only capable of going up to 2 or 300 bar, that would have been no where near enough to shoot a full 25 record targets, plus sighters, but with what you just said, no problem!

Thanks for the info.

Dave
 
but how many cc's of air does a 24" tube typically hold? and as far as the regulator goes, would i be able to get one for a 50fpe rifle?
 
I think it works out to like 546cc but may loose some to end caps even though I dish them out. I think a 50fpe gun can be regged these days.
 
Hay All I just bought 6 tins of Eley magnum 30 gr. ( hope it is not a scam ) to try in the Sumo . I have the heavy Daystates on the way , and have all heavy pellets that I know of on hand . Come on up to Salem and see if I get it all worked out . Well have the 1 and 3 place EV2 from worlds there and 2 or more Dawsons shooting HV and maybe some new uses of the Dawson .
 
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