Flex .30 modification log Refurbish, Update, Hack

[MJP]

That tube is looking good David!
Did you use straight oxphoblue or dilute it when dipping? Need quite much to dip a tube, that's why I'm asking.

Marko

[PCPhack]

Thanks Marko. I used it straight from the bottle, without dilution. I used the whole bottle in a small plastic tub. I tipped the tub up so that the Oxpho was all along one bottom edge and then dipped the tube in it while rotating it to hit all sides. I tried the regular wiping technique but wasn't really happy with how the finish came out, so I dipped it instead.

[MJP]

Thanks,
Need to test if it's better than my current method.
I'm heating the part with hot air, applying the oxpho and let it sit for couple of minutes, rinse and rub with 000 steelwool. Rinse and repeat.
That's when I'm too lazy to heat up the hot caustic bath for hot blueing.

Marko

[mackeral5]

Great thread.  Somehow I missed it before starting my Flex journey.   Great info, especially the part about WAR hammer vs Mrod hammer length. 

[PCPhack]

I am glad it has been helpful for you Mike.

I do plan to come back and post some final revuilt pictures and shot strings for accuracy, but my work became very busy. I will be back with more after 2 or 3 weeks.

[mackeral5]

Looking forward to the updates.

[PCPhack]

Someone has inquired about the oring sizes for the Cobra regulator on the Flex. Here are the rebuild notes.

[PCPhack]

Here is a screenshot of the regulator rebuild pdf for anyone having pdf issues.

Kinetic, I tried to reply to your PM, but it said my message was blocked.

[PakProtector]

Heart transplant time! Wow, whoever made this even signed it.

If that is an SS valve, you will want to re-spring I bet. A Marauder 10 lb spring and a half inch sleeve/spacer made from the shortened throat block out of a 2263 Marauder valve did the trick for me. Am miles from full pre-load, and it shoots in the mid-900's.
cheers,
Douglas

[PCPhack]

Heart transplant time! Wow, whoever made this even signed it.

If that is an SS valve, you will want to re-spring I bet. A Marauder 10 lb spring and a half inch sleeve/spacer made from the shortened throat block out of a 2263 Marauder valve did the trick for me. Am miles from full pre-load, and it shoots in the mid-900's.
cheers,
Douglas

If you see reply #25, I did respring it also, with that smallest spring. It was perfect.


In more recent updates, I have now switched the Flex to use a SS version 2 valve, the same one as in the JSAR Raptor. As the SS2 takes a little more spring to open compared to the original SS valve, I switched to the middle sized spring from post #25. I am preparing some shot figures to post.

In addition, I recognize that I never came back and posted final pictures or results of shooting groups with both slugs and pellets. I have ordered some of the newer NSA high speed machine slugs to test in addition to the one that I had earlier, so want to revisit this.

[Motorhead]

On my Warp with an SS2 type valve ... hammer weight down to @25 grams and DE-STROKED  a full .550" from original stroke. use an SSG with a 10# spring.  Making 54 ft-lbs in .22 caliber easily.

[PCPhack]

Scott, I might do an SSG later on this just working with the spring for now.

First up, slug hunting tune. Regulator at 3000 psi. 17 inch .30 barrel. 350cc bottle

55gr Mr. Hollowpoint slug
Spring 6 turns from max (this is the peak. One turn more only gave a few more fps)
893 fps
4055psi to 3938psi
.57 FPE/cuin per shot (Very inefficient getting max power)
117psi used
97FPE

65gr Mr Hollowpoint slug gave 845fps for 103 FPE.

ES across many shots is only a few fps. I love the WAR regulator together with SS valve.

With this, I can easily have 10 shots before coming off the regulator at the max fill of 4250, which is perfect for 1 magazine.


Up next will be the more reasonable and very efficient pellet tune. Stay tuned.

[PCPhack]

Pellet tune - not quite perfect but I want to post it to illustrate how sensitive the SS valve can be on the efficiency sweet spot with regard to the hammer.

Name: Flex SS2 9.5 turns out 2100 Psi regulator
JSB 44.75 pellets
Notes: 3553 to 3092 on 350cc tank
Shots: 10
Average: 859 ft/s
SD: 2 ft/s
Min: 855 ft/s
Max: 861 ft/s
Spread: 6 ft/s
Power Factor Average: 38
Power Factor Low: 38
Power Factor High: 38
Weight: 44.8 gr.
1.08FPE/cuin/shot
73 FPE
46 psi/shot

Now.... this was at 9.5 turns from max on the spring and at 2100 psi. I lowered the regulator to 2000psi and turned the spring just 1/4 of a turn out more, and voila, 38 psi per shot, and a few fps less average. This puts me at 60 shots per fill at a 4250psi fill.

Note that earlier in this thread I claimed a nice 60 shot tune on the original SS valve but I had accidently used 4500psi as a max fill using a 2250 psi setpoint. As the max fill should be only 4250 really on these bottles that 60 number from before would be on 54 shots, although the tune was slightly stronger than this one.

To be continued...

[mackeral5]

Awesome numbers out of the 17" barrel. Nice job.

[PCPhack]

Thanks Mike. I have to give credit to the great design of the WAR regulator and the SS2 valve. 

One thing I forgot to mention in my last post is that free flight of the hammer with my current spring is exactly at 9.75 turns out from max, and is why putting the spring there gave me a good jump in efficiency (high power but only 38psi per shot). A SSG would give me a bit more flexibility while keeping the efficiency higher than with just a spring alone.

[PCPhack]

Scott, I might do an SSG later on this just working with the spring for now.

First up, slug hunting tune. Regulator at 3000 psi. 17 inch .30 barrel. 350cc bottle

55gr Mr. Hollowpoint slug
Spring 6 turns from max (this is the peak. One turn more only gave a few more fps)
893 fps
4055psi to 3938psi
.57 FPE/cuin per shot (Very inefficient getting max power)
117psi used
97FPE

65gr Mr Hollowpoint slug gave 845fps for 103 FPE.

ES across many shots is only a few fps. I love the WAR regulator together with SS valve.

With this, I can easily have 10 shots before coming off the regulator at the max fill of 4250, which is perfect for 1 magazine.


Up next will be the more reasonable and very efficient pellet tune. Stay tuned.

Note in this post above I wasn't even thinking about the fact that the Flex  30 magazine only holds 7 shots, when I said a 10 shot power tune was perfect for 1 magazine. I have been single loading pellets and slugs while testing, and wasn't thinking about the right magazine.

[mackeral5]

Scott, I might do an SSG later on this just working with the spring for now.

First up, slug hunting tune. Regulator at 3000 psi. 17 inch .30 barrel. 350cc bottle

55gr Mr. Hollowpoint slug
Spring 6 turns from max (this is the peak. One turn more only gave a few more fps)
893 fps
4055psi to 3938psi
.57 FPE/cuin per shot (Very inefficient getting max power)
117psi used
97FPE

65gr Mr Hollowpoint slug gave 845fps for 103 FPE.

ES across many shots is only a few fps. I love the WAR regulator together with SS valve.

With this, I can easily have 10 shots before coming off the regulator at the max fill of 4250, which is perfect for 1 magazine.


Up next will be the more reasonable and very efficient pellet tune. Stay tuned.

Note in this post above I wasn't even thinking about the fact that the Flex  30 magazine only holds 7 shots, when I said a 10 shot power tune was perfect for 1 magazine. I have been single loading pellets and slugs while testing, and wasn't thinking about the right magazine.

I saw that, understood what you were intending to say. 

When I had my Flex, once I put the 22" barrel on I already had quite a few tuning tools--Cobra Reg, Cobra valve with 2mm stemmed peek poppet, and Rocker 1 MDS hammers in 3 different weights.  I typically ran the light hammer (28 or so grams) with .125 or so gap, with the fairly heavy OEM Flex spring.  1900ish psi reg setting.  This yielded easy 90fpe pellet tunes.   Shot consistent MOA and sub MOA at 100 yards this way. 

I just got bored with it and turned it into an Extreme .457 (via trade)......

I can only imagine the new opportunities presented with the Gen 2 SS valve.   

[PCPhack]

And now because I can't leave well enough alone, I have a 24 inch .30 barrel on the way to play with in the Flex also. It is originally from a Warp, so I am making a big assumption here that the porting and all line up the same between the Flex and Warp platforms. We will see.

[mackeral5]

And now because I can't leave well enough alone, I have a 24 inch .30 barrel on the way to play with in the Flex also. It is originally from a Warp, so I am making a big assumption here that the porting and all line up the same between the Flex and Warp platforms. We will see.

Fitment should not be an issue.  Scott uses my old Flex .30 17" barrel on his WARP. 

Things just got to be very interesting.  I will be anxious to see how much efficiency power the ss2 valve can produce. 

[PCPhack]

Well, here is the 24 inch TJs barrel in the Flex viewed through the transfer port with the barrel tensioned. Yep, I need to rework the port opening on the barrel a little. I thought that maybe I could use double washers before the clip goes on to move it back, but then the magazine won't fit. There must have been some specification variance between when my Flex was made and this barrel was made. I have a very early serial number Flex.

Then, just to make my life interesting the grub screw that helps to secure the barrel stripped at the head. I have high quality T wrenches, so it did not cause it. I will have to work it out or drill it to get the barrel back out now and replace the grub screw. I will try gently heating the aluminum with a heat gun first. Blah. I'll be back.