GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Big Bore AirGun Gate => Topic started by: mann on February 02, 2019, 10:53:12 PM
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Got my simplified balanced valve to seal up .it is a mrod 25 valve body with throat punched out to .280 and exhaust port at .175 peek poppet in a in regulated mrod tube. Valve opens easily . I got a Armada breech here and a bolt for it . Along with a couple old mags and a 30 Cal barrel it isn't the right twist but if everything else works out I'll have to order the correct barrel I'll have to sleeve the bolt to . I also got pellets now so I can do a full string in my brod 25 and see if it makes 100 shots at 50 plus ftlbs with a simplified balanced valve in it also
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30 Cal 50 gr make the 25 Cal 34 gr mk 2 look small
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Sorry about the bad pics
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Got the barrel sleeved for the breech since I had it turned down to 3/8 for my talon it's a 18 inch long barrel
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Awesome Mark, I am doing the same. Just in parts ordering phase though. How do you plan to modify the mags?
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Well the valve leaked out over night and I want to make a new poppet for it but I'm out of peek so I put in a Cobra valve which I know won't get the power I want but keeps the build moving till I get more peek. As for the mag I took it apart and sanded carefully with a dremmel tool to get 5 out of 8 in the mag had to sand around the outer edge also I'm still getting the fit to be just right that's why only 4 pellets in the pic
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It's rough but I'm hoping it will work
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Ok...seems no one is making them any more...will have to try something along those lines too.
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Does JSAR not have any? They have them listed with the custom builds in the Marauder at 65. USD
Mag's alone were listed a week ago. I don't see them now.
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I didn't try jsar I found used 25 Cal mags for sale at hill air gun for under 10 bucks I figured I could give one a try
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I just finished testing my brod 25 filled to 4500 psi reg set at about 2100 I averaged 50.04 ftlbs for a 100 shots fell off the regulator for the last 5 shots so 799 was low and 827 was my high got a average of 814 with ace care .5L bottle I'm happy with that
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If I can't get the mag to work I'll get a single shot tray or try to make one out of the mag .I might finish the upper and put it on the brod lower half just to see it can do
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Looking forward to seeing your results. I happen to have a single .30 mag that I want to build a caliber change kit (barrel/bolt sleeve) for my QB78 w/acecare 500cc bottle. it's currently a .25 with a 18.5" barrel. With LDC it's a little over 40". Currently it's tuned to 58fpe with not too bad of efficiency.
I'll be anxious to see what kind of numbers you get with your .25 powerplant and a .30 upper with a relatively short barrel.
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I'm curious about it also with 30 Cal barrel being short . The valve in it is ss valve body with simplified balanced valve poppet and thimble 31 gram hammer a ssg with 13 lb flat spring . If I changed the hammer and open the tp adjuster the valve would have enough to put up some good numbers it's a .290 throat and .200 exhaust port with a set screw to choke it down to enable me to get some more adjustment out of the valve I'll put in a .200 tp in the 30 Cal and probably a .200 barrel port think about building a shroud yet also for that upper more I think about it I may just use it as a upper instead of putting it on the other tube I have
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Well I got the mag to work today at least cycle threw 5 pellets I'll have to do some more testing with it . I'm going to make a ssg with it's own end cap so when I switch uppers I'll switch out ssg to its own and its own hammer that way I won't have to retune each time I switch from 25 to 30 Cal
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I did a 30 cal m-rod 2 years maybe less ago. Used a green mt barrel , a hill valve and breach seal, 12 lb spring and I sleaved it twice with carbon fiber. It is a very loud tack driver , get 2 mags out of it then refill to 3000 psi Top fps 983 low 907 for the 2 mags . Next shot gos to 827 and lower drops off like a rock but ok for hunting . 50 gr Exact pellet. Ported it as large as the hill seal would take , can't recall but I was worried as I polished the hole with cratek dremal. so it is big. But loud , I live in the woods so oh well. Some CO would give me heck if I put a mod on it. They still think you can't hunt with an air rifle. I carry a copy of the law in my pocket. PS got my mags from WAR for his early 30 cal rifle.Have fun
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I dont know if there are any other internal parts needed to be modified in the mag, but check out this thread: https://www.gatewaytoairguns.org/GTA/index.php?topic=143205.40 (https://www.gatewaytoairguns.org/GTA/index.php?topic=143205.40)
There are some folks in it probably can make a design for 3D printing, in fact last post Aluminumfetish offers assistance in design.
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The star inside needed to be opened and I sanded around the inside of the mag housing because I took the inside star piece down about as far as I could and still needed a little more room also had to drill out the holes to 30 Cal
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Well I ordered a lw barrel that's choked and a better twist rate for pellets
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The 30 LW is no good. Better to get the 30 pellet from TJs. I have one in a condor and it does real well. Made the finals at EBR twice with it.
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The 30 LW is no good. Better to get the 30 pellet from TJs. I have one in a condor and it does real well. Made the finals at EBR twice with it.
Don't ya think telling him AFTER he ordered is a little late? LOL!!! Good way to burst the anticipation of a new toy though. ::)
I will admit the advice is solid. Just improper edicate. If given before ordering, it would have been golden!
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Lol oh well it should be better than the one I was shooting bullets out of which I think is a 10 twist
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My bad. I thought he was going to order one. I see it said I ordered one. Oops
The problem is they slug around .306".
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Greetings.
Well yes the LW of .30 is 306 / 298. With twist of 1/16 ". And can not say that" not good "is that there is put the ammunition you need. The LW with choke goes very well with pellets below 300 m xsg.
My LW gun without choke pulls the jsb .30 hasya pellts very well over 300xxsg. And the 90 grains of this mold:
http://www.accuratemolds.com/bullet_detail.php?bullet=30-075A-D.png. (http://www.accuratemolds.com/bullet_detail.php?bullet=30-075A-D.png.)
these move between 308/297 m xsg in 10 firings first.This bullet works well just like it comes out of my mold.
It is sure that Mark will do good results with his LW barrel when he finds the minimum power setting for his 30 pellets. From 250m safely xsg, and at lower speed it is possible that too.
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I just ordered a .30 magazine from WAR which is designed for the WRAP/Flex that should work in the .30 Marauder breech after slightly milling the breech.
The advantage is that it will allow a longer slug/pellet. If the magazine doesn't work it will up for sale.
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My bad. I thought he was going to order one. I see it said I ordered one. Oops
The problem is they slug around .306".
Yep, not proper bore at all Doug. Unless willing to but a mold and sizer for it. PITA! ;)
Mike
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I was very interested in the thread PCPack had going on the W/L Poly barre, and wanted to learn more about it. Sadly,it got derailed and nasty to the point it was locked.
Doug, andy idea how they mic.?
Mike
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FYI, there is a NEW .30 cal Lothar Walther barrel which has been custom ordered by Pak Protector and others, specifically for pellets.... It will be a smaller bore (0.302-0.303" IIRC), and a 36" twist, with Polygonal Rifling.... If THAT is the barrel that Mark has ordered, he should be a lucky mann (sic)…. 8)
Bob
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Idk what ever jsar are selling is what I ordered
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Awesome Mark...have my parts coming in too. Will post in another thread when I start fiddilin' as to not hijack your thread. Barrel will take another few weeks.
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Yeah no problem I'm going to try my other barrel until the new blank gets here . I have to sleeve my bolt yet to I'll machine my barrel and sleeve my bolt on my 9 x 36 atlas it won't be perfect but ill be able to get it to work . I'm newer to machining only had the atlas for about 6 or 7 months getting better with it though
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I ordered a 15 and a 17 lb flat wire springs which seem to cock way easier than the weight suggests going to try the 15 lb first on the ssg for the 30 Cal . I might try the lighter hammer first also before I go to mass 40 gram hammer the lighter one is 31 gram
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I think you will find the 17# better, These flat springs are not rated the same way the coils springs we normally use are. Totally different. Cut as little as you can possibly get away with before coil bind.
In fact, several users have used a washer between two of the 20# springs to get the velocity they are needing, or matching what they already had, but with much lighter cocking efforts. ;)
Knife
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I ordered a 15 and a 17 lb flat wire springs which seem to cock way easier than the weight suggests going to try the 15 lb first on the ssg for the 30 Cal . I might try the lighter hammer first also before I go to mass 40 gram hammer the lighter one is 31 gram
Mark where did you order the flat springs?
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Midway USA there for 1911 recoil springs
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I just received the .30 Magazine from WAR for their .30 WARP. It is exactly the same as my Marauder .25 except it is .062" wider so I will open up the breech by that amount and it should work.
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Bob,
I spoke with Jim and his recommendation was "You would need to mill the back of the magazine pocket for them to fit" Wondering if it is just the pocket that needs to be machined?
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Bob,
I spoke with Jim and his recommendation was "You would need to mill the back of the magazine pocket for them to fit" Wondering if it is just the pocket that needs to be machined?
The measurements that I took looks like it will fit the same as the .25 magazine after .062" is removed from the rear of the magazine pocket. Hopefully I will find out in the next couple of days.
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Bob,
I spoke with Jim and his recommendation was "You would need to mill the back of the magazine pocket for them to fit" Wondering if it is just the pocket that needs to be machined?
The measurements that I took looks like it will fit the same as the .25 magazine after .062" is removed from the rear of the magazine pocket. Hopefully I will find out in the next couple of days.
Bob Pratl ,
I could be wrong but you may want to check and make sure that your bolt probe tip will have enough clearance once pulled all the way back for the magazine to cycle. Not looking at mine right now but if memory serves me right it’s pretty close. If it didn’t clear then bolt probe would have to be shortened which then in turn wouldn’t seat your bullet/pellet far enough past the barrel port. A sixteenth of an inch don’t sound like much but sometimes it call make all the difference.
Just saying,
Chris
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I think the reason I get So hi a FPS is I begged for a long barrel, It is 20 inchs from front of rec block to muzzle. And like I said the port is as big as I could get. I do have to clean it often as lead will build or wax not sure which, maybe both. I have been using bike chain wax for lube. The carbon fiber on the out side of the barrel helped out a lot for group size. And I do use a lot of air in it. It does not shoot cast slugs well however. I think you will have a ball with this 30 cal m-rod
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Bob,
I spoke with Jim and his recommendation was "You would need to mill the back of the magazine pocket for them to fit" Wondering if it is just the pocket that needs to be machined?
The measurements that I took looks like it will fit the same as the .25 magazine after .062" is removed from the rear of the magazine pocket. Hopefully I will find out in the next couple of days.
Bob Pratl ,
I could be wrong but you may want to check and make sure that your bolt probe tip will have enough clearance once pulled all the way back for the magazine to cycle. Not looking at mine right now but if memory serves me right it’s pretty close. If it didn’t clear then bolt probe would have to be shortened which then in turn wouldn’t seat your bullet/pellet far enough past the barrel port. A sixteenth of an inch don’t sound like much but sometimes it call make all the difference.
Just saying,
Chris
Chris, you may be right about the probe clearance but after I machine the Mag pocket I'm planning to mill in a J-hook slot to retract the bolt once the pellet is seated so hopefully I will be able to modify the breech for the wider magazine to clear the prob. Worst case I would have to fabricate a new breech and start all over. The problem is that I have the equipment but not the time.
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Well I got my bolt sleeved and tried out the magazine with the bolt I have to do some fitting yet to get it to line up a little bit better but it will chamber a pellet . Also made another ssg with the original end cap and 15 lb flat spring . It compresses far enough I may be able to use it as it is which is 4 inches long
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I'm planning on a shroud I found aluminum tubing at my local hardware store once I get the other barrel I'll get the aluminum tube and make a full shroud for the 30 Cal upper
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Well I put the upper on my bottle rod tonight with a heavier hammer and 15 lb spring simplified balanced valve haven't adjusted transfer port yet for .200 all the way threw it's probably about 170 or a tad less . Took 3 shots messing with the ssg a little bit 641 643 and 642 fps. I know my transfer port is choking it down since I had it adjusted to just 50 ftlbs with the 25 Cal . I milled out so the bolt gets pushed all the way forward and then comes back to the original channels on the side also did this to my 25 upper it pulls the bolt back about a 1/8 inch from the the pellet so far so good just need more fps this barrel is only 18 inches long to so that doesn't help any
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Pic with it on my bottle rod it will be nice to have to 2 different Cal uppers
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Well I hit 724 by opening the transfer port screw open and with a short barrel which is like 17 3/4 inches or something like that I should be able to get to 800 at least with a 24 inch barrel this is also regulated to 2100 from the 4500 bottle low 800s to mid 800s for fps I'll be happy with I got some more messing around with the magazine yet to do also
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740 fps with 18 inch barrel .200 porting and 50.15 jsb pellets 15 lb flat wire spring and a mds 45 gram hammer
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My Yong Heng blew a burst disc made one out of a pellet tin also found a couple loose fittings probably from heating and cooling it gets up to 60 degrees and I had to cycle it a few times to get my large 88 cuft up to 4000 psi doesn't take to long even with the cycling it's still faster than the shoe box which I now have for a back up I'll have to refreeze my jugs of ice and finish topping it off tomorrow
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Got the mag almost completely working I got one pellet out of the 5 that is getting hung up alittle more tweeking and I should have it working I can't wait for the other barrel so I can build a shroud this thing is loud with out one
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I picked up the aluminum tube for the shroud today and found 7/8 wooden dowl fit inside snuggly and decided to try use it for the shroud baffles which seems to work
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Got the barrel the other day finished machining and put in a .200 tp hole put it on the lower and tried it with 45 gram hammer 15 lb flat spring on a ssg barrel is 24 inches first couple shots 790 792 almost 800 which is where I want to be I may have to try the 17 lb spring yet
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I switched to 17 lb flat spring and found I was having a lot of air escaping by the bolt even though it was half way tight fit so I took and machined a spot for a oring in the bolt and that got me to 819 and 814 fps at a 2100 set reg with about 70 cc plenum 50 gr jsb pellet
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Climbing on up there! Curious on how you turned the bolt for the seal? I have read it is a bear to get the cocking handle off of the Marauder bolts.
How is the moderator working out?
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I chucked it in the lathe with the handle between the jaws
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I'm still in the process of making the shroud it will be 32 inches long
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I look forward to seeing the final build. You have made great progress so far.
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Well I got the shroud built and on with 11 baffles it's about a 1/4 inch longer than than my 25 upper with a 5 inch ldc on the end of the shroud still have to get some paint and paint it up also need to find a slow leak in my bottle lower
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Great build going to follow
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So I couldn't get the magazine to work one pellet out of the 5 was giving me problems other was cocking off to side some and would bind up the mag I sanded the holes to wide . I'm going to cut apart the mag and make it into a single shot tray I'll fill the areas with jb weld and groove out a new area for the tray and pellet to line up in
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I haven't had a chance to try any more shots for tuning or see how my shroud works yet my Yong Heng developed a leak at the high pressure outlet on top of the cylinder and have been trying to get it sealed up. The simplified balanced valve I'm using in the tube for the 25 Cal and 30 with the 30 Cal and the tp wide open at .200 was blowing open and I only got like 10 shots out of the 4500 psi bottle . I may also have to switch to the lighter hammer like I'm using in the 25 . I thought
About trying the war Cobra valve in my spare tube to see what it would do .
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Well my simplified balanced valve started leaking and I'm sick of messing with it and a few other things so I ordered a cothran valve for the 25 bottle rod and figured it would be good to use it on the 30 cal upper debating on getting a adjustable reg from jsar for it to
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I'm still waiting on my Big Bore Balance Valve, from JSAR, to finish my Mrod conversion. A carbon fiber bottle and Adjustable regulator are in the horizon.
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The cothran valve is supposed to be here tomorrow my plan is to put it in the bottle rod and change the transfer port .make one to .200 size to fit both the 25 upper and 30 upper. I may have to make one that is choked so I can run the same reg pressure for both and just swap out the upper and transfer port and run with the same reg setting which I may have to drop some with the cothran valve
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Keep plugging away, making progress.
Did you order a .250 port Cothran? If so why not go .250 on the transfer?
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I'm not sure I don't recall see transfer port size at war when I ordered the only reason I didn't want to go .250 is I'd have to use oblong port and I haven't tried that yet I've been able to go to .200 with a normal hole and didn't lose any accuracy and it's providing the power I want from my 25 brod
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The 30 cal upper might be able to use the larger port though
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Ah, I see. I didn't consider being able to switch calibers....
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I used .200 inch wide porting in my .25 disco and had no loading problems, so in .30 cal I think you would be able to use a bit bigger hole.
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Yeah probably I tried a 1/4 inch hole in the 30 cal barrel I had laying around with some Dremel work around the whole I could probably get it to be all right
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thought I would add an option here. I use the oval port system, but as my gun is a switch barrel, what I have done in addition to the barrel port is use a diamond ball, and bevel the inside (bore) of the port lower than the rear of the port, then polish with rubber abrasives. (think polished feed ramp similar to a ported semi auto handgun).
this has two functions. First the projectile cannot get caught or shaved by it, and secondly, it helps the air charge to turn in the direction of the projectile, not just straight up into the roof of the barrel. Same trick I used in porting cylinder heads for racing for years.
I also bevel the bottom of the rear of the barrel port and polish it. As the bullet or pellet is traveling down the bore, this helps the air bend in the path more easily, Giving higher air velocity with less turbulence.
Flow bench numbers in racing heads have proven this technique out. Both in naturally aspirated applications, as well as under pressure from Superchargers and Turbo setups. Increasing flow at a given pressure. Our guns work the same, just in micro. LOL ;)
I have seen Mr. Bob use something similar in machining the port in the valve itself at an angle to start the process. 8)
Knife
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Yes when I went to .200 in my .25 I took a dremmel and made it like a feed ramp which did work out well just I got it ported to .200 and my other valve was making around 75 to 80 ftlbs don't really need any more than that I have a 257 with a noble valve and a recluse 357 that is about 180 ftlbs to 190 after I modded the valve and stuff . So around 80 ftlbs is good
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;) + 8)
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I got the cothran valve the other day I'm going to install it today and since I have a hm1000 x 25 Cal I'll just leave the 30 cal upper on the bottle rod I'm going to use derlin to machine a tp an that will taper down to .200 at the barrel and see what I get with 50 gr jsb ill use my peek hammer and a light spring probably with a ssg also I'll get some pictures when I get out to the shop and get some stuff made up
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Cothran valve is going into the tube it has the 250 port so I made a nylon transformer port that tapers from 250 to 200 fits in the top of the valve snuggly
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Well I drilled a bigger hole in the air tube got the new transfer port fitted into the breech put in about a 35 gram hammer and a lighter spring on the ssg then finished my single shot tray put the whole thing together and the first shot was 569 fps reg is set to 2100 psi so I readjusted the gap and took another shot 863 with 50.15 gr jsb pellets
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Here is it all together except the stock
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It's 4 to 6 inches longer than regular Marauder
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Here is the shot string 32 shots from 3600 psi fill on the bottle down to 2000 with 82 ftlb average Ave fps is 862
1.863
2.867
3.861
4.859
5.860
6.859
7.865
8.863
9.861
10.862
11.863
12.863
13.863
14.864
15.866
16.864
17.862
18.867
19.863
20.865
21.865
22.863
23.866
24.864
25.865
26.861
27.863
28.865
29.864
30.859
31.859
32.851. Off the regulator
Jsb 50.15 pellets. I'm happy with it . I'll probably paint the shroud flat black later on
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I got to get a scope on it and shoot for accuracy yet maybe I'll get to it tomorrow yet
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Very very impressive Mark!
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Very nice!
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Woo-Hoo, Don't ya just love it when a plan comes together! ;) 8)
Now, what is that last picture?
Mike
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It's a single shot tray I made from a 25 Cal used magazine I got from hill airgun cheap
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Thanks everyone took a bit to make my mind up and I figured with having a hm1000x in 25 I decided to dedicate the brod to a 30 Cal and I'm happy now with the cothran valve
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Well I got the scope on it and got it pretty well sighted in to 55 yards here's a group not the greatest but not bad a bottle cap covers it 5 or 6 shots in it
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That cothran valve really made a huge difference. Think it would work well in a 25 caliber as well?
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Yeah it uses a lot of air but with a regulator it works good . In a 25 I'd stick to heavy pellets and you might have to dial the regulator back depending on your port sizes
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Nice work Mark!