New to me Flex .30--- Added shot strings

[Bob Pratl]

Mike, what hammer and slug combination seems to work out the best?
Everyone is correct, David is first class and a pleasure to deal with. I purchased a few LDC's and a Airforce Edge from him for my grandson, and he proved to be a real gentleman.

[mackeral5]

Mike, what hammer and slug combination seems to work out the best?
Everyone is correct, David is first class and a pleasure to deal with. I purchased a few LDC's and a Airforce Edge from him for my grandson, and he proved to be a real gentleman.

Bob, I don't quite know yet.  So far most of my testing has been with a 2250psi reg setting and JSB 44 and 50gr pellets.  I briefly tested unregulated with NSA 60gr, but only had 25 to test with.  Also, the valve currently installed is significantly modified---a Gen 1 WAR valve with peek poppet, 2mm stem, and an add-on Cobra chamber.  Chances are whatever results this combination likes won't directly translate for other guns.   I have both WAR Cobra and Cothran valves, at some point i plan to test with them. 

Tuning for 100+ fpe is very new territory for me.  All of my previous  tuning is around light hammers and fast hammer strikes.  For the 103fpe unregulated tune i used a 55 gram hammer

[Bob Pratl]

Mike, what hammer and slug combination seems to work out the best?
Everyone is correct, David is first class and a pleasure to deal with. I purchased a few LDC's and a Airforce Edge from him for my grandson, and he proved to be a real gentleman.

Bob, I don't quite know yet.  So far most of my testing has been with a 2250psi reg setting and JSB 44 and 50gr pellets.  I briefly tested unregulated with NSA 60gr, but only had 25 to test with.  Also, the valve currently installed is significantly modified---a Gen 1 WAR valve with peek poppet, 2mm stem, and an add-on Cobra chamber.  Chances are whatever results this combination likes won't directly translate for other guns.   I have both WAR Cobra and Cothran valves, at some point i plan to test with them. 

Tuning for 100+ fpe is very new territory for me.  All of my previous  tuning is around light hammers and fast hammer strikes.  For the 103fpe unregulated tune i used a 55 gram hammer

Mike, I started converting my .25 Marauder to .30 last December by purchasing a TJ barrel which I received within days and a JSAR Big Bore Balance valve which showed in stock at that time but unfunctionally it was out of stock so presently I have been waiting 5 months for their upgraded valve so the gun is still in the disassembled stage waiting for the new valve. Travis suggested a 50 gram hammer and stock spring as starting point.

[mackeral5]

Mike, what hammer and slug combination seems to work out the best?
Everyone is correct, David is first class and a pleasure to deal with. I purchased a few LDC's and a Airforce Edge from him for my grandson, and he proved to be a real gentleman.

Bob, I don't quite know yet.  So far most of my testing has been with a 2250psi reg setting and JSB 44 and 50gr pellets.  I briefly tested unregulated with NSA 60gr, but only had 25 to test with.  Also, the valve currently installed is significantly modified---a Gen 1 WAR valve with peek poppet, 2mm stem, and an add-on Cobra chamber.  Chances are whatever results this combination likes won't directly translate for other guns.   I have both WAR Cobra and Cothran valves, at some point i plan to test with them. 

Tuning for 100+ fpe is very new territory for me.  All of my previous  tuning is around light hammers and fast hammer strikes.  For the 103fpe unregulated tune i used a 55 gram hammer

Mike, I started converting my .25 Marauder to .30 last December by purchasing a TJ barrel which I received within days and a JSAR Big Bore Balance valve which showed in stock at that time but unfunctionally it was out of stock so presently I have been waiting 5 months for their upgraded valve so the gun is still in the disassembled stage waiting for the new valve. Travis suggested a 50 gram hammer and stock spring as starting point.

While I don't have any experience with Travis' valve, his advice sounds reasonable.  it sounds like you're building an unregulated gun?  If you were going regulated I would have suggested ordering either a WAR Cobra or a Cothran valve, as they are both readily available.

[Dairyboy]

I too plan on going the route of the SS valve in my Flex. But mine is unregulated as well.

[mackeral5]

I too plan on going the route of the SS valve in my Flex. But mine is unregulated as well.

And I'll be watching, it may prompt me to add one more valve to my Flex parts bin....

[Bob Pratl]

While I don't have any experience with Travis' valve, his advice sounds reasonable.  it sounds like you're building an unregulated gun?  If you were going regulated I would have suggested ordering either a WAR Cobra or a Cothran valve, as they are both readily available.

I would eventually like to regulate it for more consistent shots as I can live with less power.

[Dairyboy]

I too plan on going the route of the SS valve in my Flex. But mine is unregulated as well.

And I'll be watching, it may prompt me to add one more valve to my Flex parts bin....

Lol yeah it's nice to have choices for the valves. My plan is to go to slugs. Nick's got 47gr and 50gr slugs that are supposed to be accurate in the TJ barrels. I ordered 100 of each. Probably will buy some sizing dies also. Only thing is my barrel has a choke...hoping they work will slug the barrel tonight and see what I'm working with. Could always cut the choke off and rethread 

[mackeral5]

Still loving the Flex.  It shoots at least as accurate as my Edgun R3M at 85 yards, which is better than I can shoot.  I shoot the same groups with both guns.  I have made a couple of slight changes so it was time to update the thread. 

The current tune is JSB 44.75's around 905fps, which is good for 30-35 shots.  It is amazing how efficiency drops off when going from 875fps to 905fps---when tuned for 875 it gets 50+ shots.  But accuracy seems to be improved at 905fps.  It doesn't seem to like the 50.15gr so much. 

I installed the 1/2-20 tensioning nut and ended up drilling out my .25 Sumo to .30.  Sound wise, this was a slight improvement over the Gen 1 Flex LDC. 



After much back and forth internal struggle, bordering consternation lol, I took the plunge and vented the shroud.  Venting was the answer----this combined with the Sumo yielded a backyard friendly reduction in muzzle blast, at least as backyard friendly as I need it to be.  I no longer feel the burning need of finding and purchasing a Shogun. 



Once the Cobra regulator/Acecare 500cc bottle combination was installed, there is no room for taking advantage of the adjustability built into a Gen 1 Flex bipod mount.  So I ordered some 6065 aluminum rod and some Ti rod.  After testing the 6065 aluminum for rigidity i chose it as the replacement material for the SS adjusting rods.  The Flex went on a slight diet, losing 3.5oz, lol...  I think it looks better, no longer having the ss rods protruding into the forearm/handle area.

[Dairyboy]

Looks great! I like what you've done with it. Have you tried the 50gr pellets at over 900fps? I heard they like faster speeds but haven't tried them myself as usually the 45gr ones are better

[mackeral5]

Thank you Dillon.  I appreciate your help in getting it together.  I have yet to test with reg pressures above 2250psi (somewhere around there).  With the current tune this puts 50gr up on the plateau around 880-890fps.    Experience has shown with my home brewed Cobra chambers the plateau occurs 25-40fps lower than it would without the cobra chamber.  So in a normal  valve configuration the plateau would likely be around 925fps.  I may bump the reg up a bit and see how that changes things with the 50gr. 

I really like the 25gram hammer that Rocker1 made, coupled with a peek poppet it makes for a very snappy shot cycle.  it is a very sharp POW, very similar to the sound of a powder burner.  Zero noise out of the action, but I do hear a very faint, dull ping in the plenum.  Compared to when I first got it (with the heavy gen  1 hammer) it is a totally different gun.  Honestly I was very disappointed when I first shot it due to the almost violent slamming and clanging of the gen 1 hammer.....I'm glad that is behind me. 

[Dairyboy]

Yeah I'm happy to help! That's alot of power though from a 17" barrel and 2250psi reg set for sure! Yeah I'm really liking the cobra in mine it seems to do a good job and make good power but I keep thinking man what would an SS valve do in this...benefit of balanced valve but get the bell curve like a traditional valve unlike the cothran.

Yeah I heard people had good accuracy with them at 950fps even but your shot count diminishes fast!! Yeah the lighter hammers really make a big difference in these guns. I'm surprised how much recoil mine has now compared to being tuned at 85fpe.

[mackeral5]

This evening I finished making a transfer port for a Cothran valve.  The Cothran doesn't have a "step" in the valve exhaust like the Flex does.  This took some creativity on my part, but after a lot of thought I found a series of operations that would allow me to make a transfer port.  I have brass hobby tubing from the smallest size all the way up to 9/16, I have all sizes in between.  So I assembled a few pieces , soldered them together, and cut them to size by chucking the tubing in a drill and spinning at high speed while slowly tightening a tubing cutter to get through the layers.  This is what I ended up with.  On the right is the OEM WAR Flex transfer port, on the left is my home grown version designed for a Cothran valve on one end, the WAR pattern on the other.



With my Cobra reg set at 3000psi, the Cothran produces these numbers:

NSA 66gr 860fps
JSB 50.15 950fps
JSB 44.75 990fps
NSA 55 915fps

I shot a string of JSB 50gr, starting with a full fill of 4500psi I got 15 shots averaging 950fps before falling off reg.  Efficiency sux, but I guess not too bad considering the 17 inch barrel. 

Tomorrow i plan to see if the 50gr group any better at this energy level----previously in the mid to high 800's they weren't as good as the 44's.  I will also try the NSA's.

[KnifeMaker]

Well done, and very nice AG!


Knife

[mackeral5]

Thank you Michael.  The Cothran is easy to open, makes good power.  But there is only so much a .25" port will flow, no matter how easy it is to open.   Thus power is pretty much in line with what I've seen with my mod'd gen 1 valve.  Actually I think my valve can do a little better than the cothran but it will require more hammer strike to do so....

[mackeral5]

Cothran valve with 3000psi reg testing....all shots at 90 yards.  I found 5 more yards in my home range....



NSA 55gr at 915fps
NSA 66gr at 870fps

Lower target is the 55gr.  Upper right bull is the sighter...  Center bull and upper left bull are 2 attempts at grouping.  Upper target is 66gr with no scope adjustments after zeroing with the 55gr.   Each bull has a 5-7 shot group. The 2 weights grouped similarly, but I ran out of 55gr quickly after getting it sighted in.  The 66's "felt" better though.  Best 5 shot group of 66's was 1.75" 





I made no scope adjustments and shot some JSB's.   The grouping left of the center bull is 44gr.  The 4 shots in the vicinity of the lower right bull are indicative of my experience with the 50gr. 

The 44's don't like running 990fps....  The 50's don't like any tune I've thrown at them from 850fps -950fps.  I'm pretty much done with the JSB 50gr. 

The 3 shots just off target to the left are 3 shots taken with a cast pellet that was graciously sent to my by shamu25.  they are 45-46gr and previous testing running them in the high 800's didn't do as good.  These 3 shots look promising--I will run a couple over the chrony and try a couple more groups with them.  They must be running somewhere above 950fps and it appears they like it. 

For this testing
JSB 44gr at 990fps
JSB 50gr at 950fps



I may clean the barrel and do some more testing with the 66gr and see if they tighten up any.  So far not a bad start for 110fpe and a 17" barrel.

[mackeral5]

Was in the middle of shooting groups after a barrel cleaning and things were going well, groups were indeed smaller than before.  Then things went sideways.  All of the sudden I couldn't hit the target.  Inspection found the barrel snap ring had worked its way loose.  Several attempts at resecuring failed.  I'm going to try and locate another snap ring of appropriate size/strength.  Hopefully this will solve it vs. the barrel groove/shoulder being rounded off.....

Going to post a Flex/Warp barrel snap ring question in the main PCP forum.....

[mackeral5]

Got her back up and running.  I ended up lapping the snap ring groove deeper by putting valve grinding compound in the groove, installing a new snap ring, then spinning the barrel  while holding one ear of the snap ring with a pair of vice grips.  This resulted in squaring the groove back up where it had somewhat rounded over when it pulled through the original snap ring.

I removed the Cothran valve and put in the WAR Cobra.  Dialed reg pressure down from 3000psi to a more modest 2400psi then dialed in the hst for a nice pellet tune--JSB 44's are running 920fps.  I also went back with the original WAR LDC to see how it does with a vented shroud.  it's a little louder than the Sumo, but not much. 


12 rounds of JSB 44 gr at 90 yards.  This is one of those 4" gongs from Wally World. 

[KnifeMaker]

This is looking really Good Mike!


I love it when someone shade tree engineers a successful way to conquer a problem.


Way To Go Mike!


Mike

[mackeral5]

This is looking really Good Mike!


I love it when someone shade tree engineers a sucessful way to concer a problem.


Way To Go Mine!


Mike

Thanks Mike. 

I made an interesting observation today when switching from pellets to slugs with no other changes.

Right now it is tuned for JSB 44gr at 915fps and the scope is zeroed at 90 yards.  Switching to NSA 55gr running 845fps results in similar sized groups (1.75") and 1.5" HIGHER point of impact.  It's amazing what difference BC makes.....  a much heavier projectile running 70fps slower hits 1.5" higher at 90 yards.