Author Topic: FAS 6004 Longer Barrel Project (Read 9036 times))

JCBinWV · « **Reply #20 on:** December 07, 2017, 12:12:02 PM »

Lookin good Gary! You're almost there... what's next OD tapering of the barrel so you can reassemble?? Can't wait to see the finished results!!

And yes - it was the top edge of the bulkhead chewing up my o-ring. That was addressed last night w/ some 400grit that i had laying on the bench from this past weekend's barrel breech & lead-in polishing efforts. Re-positioning the o-ring to a fresh uncut position tonight to confirm, and then placing an order for a small assortment of 010 o-rings (square, round, 70d, 90d, urethane, etc) to see if one works better than another for the breech seal.

Good idea on the outside radius chamfer! Gonna borrow that one too!!

thanks!
jc

WyoMan · « **Reply #21 on:** December 08, 2017, 02:38:11 AM »

Glad you got it sorted out, JC.
The oem breech seal is metric 1.78 x 6.75mm. Hard to find. And not many choices other than Viton. Maybe another size will work. It's kind of in between a number 010 and 011.

More work on the barrel... it's starting to look like the drawing

The last 4" was turned to .375" to fit inside the sleeve. The section inside the frame was turned to .398"... a few thou oversize. I'll cut it some more if I need to.
Now I have to profile the breech section and then I'll turn the last 1/2" (section inside the frame) to fit the bore in the lever...

Wyo

Bob Pratl · « **Reply #22 on:** December 08, 2017, 06:35:34 AM »

Gary, it's looking good. I'm anxious to see the finished product and see how it performs.

Rob M · « **Reply #23 on:** December 08, 2017, 10:35:02 AM »

Quote from: WyoMan on December 08, 2017, 02:38:11 AM

Glad you got it sorted out, JC.
The oem breech seal is metric 1.78 x 6.75mm. Hard to find. And not many choices other than Viton. Maybe another size will work. It's kind of in between a number 010 and 011.

More work on the barrel... it's starting to look like the drawing

The last 4" was turned to .375" to fit inside the sleeve. The section inside the frame was turned to .398"... a few thou oversize. I'll cut it some more if I need to.
Now I have to profile the breech section and then I'll turn the last 1/2" (section inside the frame) to fit the bore in the lever...

Wyo

VERY NICE WYO , question.... How does the LW metal cut , you running carbide ??

JCBinWV · « **Reply #24 on:** December 08, 2017, 04:58:02 PM »

Nice progress, Gary!

I'm not sure if i'd call mine "sorted", quite yet, but feel like I'm making progress with your help! lol I saw the metric size for the breech o-ring but didn't bother trying to find metric. I based my small assorted order on a thread I found over on TargetTalk (ok to reference that here on GTA???) where he referenced the 010 size and got favorable results.

Are you still waiting on extra tooling/material? or are you getting close to reassembly?

thanks again for the info!
jc

Hoosier Daddy · « **Reply #25 on:** December 08, 2017, 07:32:31 PM »

DUDE..... that is gonna be HUGE!

WyoMan · « **Reply #26 on:** December 08, 2017, 10:31:34 PM »

Thanks, guys.

Rob, the LW steel is a lot tougher than what's in a Crosman barrel. They say it's CrMo on their website.
The chips come off small and it wants to get hot fast. I've used carbide and cobalt HSS but I'm no expert.

JC, if the 010 o-ring doesn't work and you need the oem metric, PM me your mailing address and I'll send a couple.
I saw right away I was going to need a metric boatload of those

Wyo

WyoMan · « **Reply #27 on:** December 08, 2017, 10:51:08 PM »

Finally finished the longer barrel (11-1/2"):

I didn't need to cut the taper because I had plenty of clearance and the step was easier:

The latch assembly was removed or there would be no chance of getting this in. I had to turn down the section that fits into the clamp from .398" to .395". I made a rough finish... better securement?

The barrel is dropped in:

It can be pushed forward now with the .395" section going inside a snug fit into the lever bore.

The .395" section has a slight recess to the outside of the lever:

Finished with the weaver mounts:

Then I attached the sleeve / brake:

I guess I need to shoot it now

Wyo

Rob M · « **Reply #28 on:** December 08, 2017, 11:46:59 PM »

looks awesome , excellent workmanship!@

Bob Pratl · « **Reply #29 on:** December 09, 2017, 06:00:10 AM »

Gary, great job, i'm impressed. Was there any noticeable added force in cocking with the added .010" shim on the piston?
With the added barrel length and the increased pressure, what have you estimated the increase FPS will be?

Bob Pratl · « **Reply #30 on:** December 09, 2017, 06:33:29 AM »

Gary, I forgot to ask. Did you special order the LW .472" barrel and why? In going the LW's site I see that the stocked diameter for the .177 choked barrel is .630" OD x 23.8" length and all others take 4-6 weeks delivery. You got me following your footsteps as it looks like a fun project.

WyoMan · « **Reply #31 on:** December 09, 2017, 10:24:19 PM »

Thanks again!
Bob, I special ordered the 12mm blanks because I heard they have better QC, but mainly because I didn't want to turn the extra 160 thou

I can notice a small increase in closing effort due to the increased compression. It's small because the last .010" of piston travel occurs where the lever has its greatest mechanical advantage.

Wyo

WyoMan · « **Reply #32 on:** December 09, 2017, 10:55:16 PM »

I ran a shot string over the chrony...

The original had an average of 308 fps with an E.S. of 4.
With the piston shim and longer barrel it's at 360 fps average with an E.S of 4. I really like the low E.S.

The 52 fps gain was a 33% increase in fpe.

First 20 shots on paper:

I'm guessing that it will get even better after enough lead down the pipe... polishing the bore.
I shot the above groups rested with some sight aid. It's fun to see a small dot in your sight picture:

It was a fun project -

Wyo

Rob M · « **Reply #33 on:** December 09, 2017, 11:01:23 PM »

awesome outcome !!!!!!! nice work..

WyoMan · « **Reply #34 on:** December 09, 2017, 11:09:20 PM »

Thanks, Rob. I need to shoot it some more (a lot more)... been somewhat busy with the honey do list this w/e.
Wyo

Rob M · « **Reply #35 on:** December 09, 2017, 11:25:37 PM »

be nice to plumb in 30 psi of shop air , then pump it ( hmmmmm, might be worth trying on a p17 lol ..

Bob Pratl · « **Reply #36 on:** December 10, 2017, 07:04:24 AM »

Gary, what did you use for the barrel break and is it steel or aluminum?
How do you find the balance with the extended barrel?

JCBinWV · « **Reply #37 on:** December 10, 2017, 12:21:52 PM »

Very impressive outcome and workmanship!

The gun with the factory barrel sits so nice in the hand, I'd bet even with the longer barrel, the FAS would be less muzzle heavy than my IZH 46m.

I meant to ask you - why did you make the "cocking buffer" out of leather?

So... When will you start taking orders?

jc

WyoMan · « **Reply #38 on:** December 10, 2017, 10:00:04 PM »

Quote from: Rob M on December 09, 2017, 11:25:37 PM

be nice to plumb in 30 psi of shop air , then pump it ( hmmmmm, might be worth trying on a p17 lol ..

A pcp ssp? Why not, there are some variations of that... The ACP platform, and of course the pressurized displacer piston / chamber... Ron Burnett made a very powerful SSP using a pressurized displacer setup...
http://www.network54.com/Forum/79537/thread/1257727426/SSP+rifle----------discovering+what's+possible.

But I'm ok with 360 fps from this pistol... especially since it's very easy to operate. The original 308 fps was too low. Folks at lower elevation are probably fine with this pistol as-is. Thanks-

Wyo

WyoMan · « **Reply #39 on:** December 10, 2017, 10:07:41 PM »

Quote from: Bob Pratl on December 10, 2017, 07:04:24 AM

Gary, what did you use for the barrel break and is it steel or aluminum?
How do you find the balance with the extended barrel?

Bob, the brake is anodized aluminum, the sleeve is Delrin and the barrel is pretty thin in that section (.375")... not much weight out there. It balances fine.
With the scope attached, that's a different matter

Wyo

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FAS 6004 Longer Barrel Project

Author Topic: FAS 6004 Longer Barrel Project (Read 9036 times))