Author Topic: Brod build: 100 FPE; stock barrel; shot pic updated (Read 12545 times))

PCPhack · « **Reply #60 on:** April 02, 2018, 04:30:59 PM »

Quote from: oldpro on March 23, 2018, 08:49:46 PM

Quote from: PCPhack on March 23, 2018, 08:46:16 PM
I just noticed that my air tube has a hole for a factory valve meter screw. Arghh. Why, why, why. Why would I need that hole there when I also specifically had the transfer port hole specified for a JSAR valve.
Due to numerous complaints all tubes have them now its tied into the C&C program.

Ah, ok. Understood. I will just hit that spot of the valve with a drop of black paint or something.

PCPhack · « **Reply #61 on:** April 12, 2018, 01:14:08 PM »

Update:

Travis indicated that the reason my WAR bottle regulator didn't screw all the way down is the need for a few more thread turns down in my tube. So I sent him my tube, and this burns yet another week in wait time.

In the meantime, I am thinking about an additional barrel. Originally, I was very interested in a 257. However, with the off chance that I might ever try it with game and the new Texas rules, I am thinking about a .308. This might also make it easier to fit heavier slugs in the breech without having to make a long cone slot along the edge to get the slug in the gap (or at least a smaller one if it is still needed). This will also maximize what the build is capable of in several areas (plenum, biggest possible barrel with breech block, etc).

PCPhack · « **Reply #62 on:** April 23, 2018, 06:18:21 PM »

Update:

Parts will be ready this week for the .25 factory barrel build. I am starting to get excited for this one.

After an enlightening discussion with Travis, I have moved the .308 idea to the next project, as I want to also tension that barrel. So a whole other upper/breech bored out for a larger barrel diameter (for stiffness) and pinned from the sides for the tensioning will be in the requirements.

PCPhack · « **Reply #63 on:** April 26, 2018, 10:06:44 PM »

Update:

The machine work is done. Now waiting on the JSAR shipment so I can assemble the Brod. I am hoping to assemble everything and start tuning next week.

PCPhack · « **Reply #64 on:** April 26, 2018, 10:12:43 PM »

Quote from: shorty on February 23, 2018, 06:15:36 PM

Bob, are you talking about the common J slot ?

I think Lloyd made a retractable lever design (one time off) years back

If you are talking about the one he has a YouTube video for, where the bolt recedes when the lever is pushed all the way down...I wish someone would offer those, and with a pic rail on top.

PCPhack · « **Reply #65 on:** May 04, 2018, 03:56:30 PM »

I received the parts from JSAR.

The retracting bolt breech mod could only be done on one side, not both due to the hammer cocking bolt head that needs to be pushed back by the similar one on the bolt, and needing to retain a side for them to slide along. So the retracting bolt is right handed.

The full bore porting is set up to us .25id tube, NOT the JSAR large metal transfer port. This is due to the close proximity of the mag well. If the port is opened up enough for the JSAR metal transfer port, then it would break through or leave that side too weak, creating a safety hazard.

They did a great job of threading the barrel end for my metal air stripper, as well as adding more threads to the JSAR air tube end to fully seat my WAR bottle regulator.

Time to assemble it all!

PCPhack · « **Reply #66 on:** May 04, 2018, 06:51:38 PM »

I did a quick build-up, and the valve has a leak. Time to tear it back apart and find out if there is a torn poppet oring, or it needs burnishing.

Edit: OK, the leak is fixed. I opened the valve, wiped everything down, did a quick poppet spin with a drill, Krytoxed everything, and reassembled it. I will have to do an overnight test to be sure it doesnt have a slow leak.

Hoping to do some initial tuning tonight.

PCPhack · « **Reply #67 on:** May 04, 2018, 10:50:11 PM »

Initial results are not so good. I am shooting the 43gr Eunjins at only 850 fps. Before the retractable bolt modification, I was getting a little over 900fps. I changed the breech oring, but this did not help. More hammer is not imcreasing it, and I suspect that either the tube transfer port needs reseating, or the dwell is too short. I will check the transfer port first and then if this doesn't resolve it, pull the jet out of the valve just to test.

PCPhack · « **Reply #68 on:** May 05, 2018, 12:01:43 AM »

TP was fine. I pulled the jet, and was off to the races... 43gr Eunjin hit 955 FPS. Tired, so stopped right there for tonight. The valve behaves quite different now with the newer internals, compared to before. I will start tuning tomorrow.

PCPhack · « **Reply #69 on:** May 05, 2018, 01:11:19 AM »

I remembered my custom heavy slugs, so did one final test for tonight.

65gr boattail, turned the hammer in, and got 833 FPS!!! That's exactly 100 FPE, which was the goal. No idea about accuracy yet obviously, bit I'm happy to see that goal met.

Tuning and shot strings tomorrow!

screwwork · « **Reply #70 on:** May 05, 2018, 05:16:18 AM »

Nice job on hitting 100 fpe David! Congrats, your hard work and patience has paid off.
Post up a picture of the Brod when you get a chance.

PCPhack · « **Reply #71 on:** May 05, 2018, 12:55:16 PM »

Thanks Randy!

I set the scope and rangefinder on top for a quick picture. There is still a lot to do in terms of tuning, and setting it up.

I will likely add a neoprene band to the carbon fiber tank to cover the white label, or wrap the front components with camo wrap.

YEMX · « **Reply #72 on:** May 05, 2018, 03:22:54 PM »

She is purdy!! I can't wait to read more!!

rsterne · « **Reply #73 on:** May 05, 2018, 03:54:08 PM »

What output pressure are you running on the tank block to get your 100 FPE with the 65 gr. bullet?....

Bob

PCPhack · « **Reply #74 on:** May 05, 2018, 04:06:02 PM »

Quote from: rsterne on May 05, 2018, 03:54:08 PM

What output pressure are you running on the tank block to get your 100 FPE with the 65 gr. bullet?....

Bob

3300 psi.

Barrel port is .2 round (not oblong)
JSAR valve and TP are .25
Valve screws are stainless, not factory. Travis called them upgraded, but I won't push my luck too far.

Hobbyman2007 · « **Reply #75 on:** May 05, 2018, 04:36:07 PM »

Nice build . I’m wondering why crosman has yet to build a bottle gun . I know I would have a real good look if they offered one .

rsterne · « **Reply #76 on:** May 05, 2018, 05:10:54 PM »

Stainless screws are not necessarily stronger than the stock screws, it depends on the grade of SS....

https://www.gatewaytoairguns.org/GTA/index.php?topic=127914.0

Bob

PCPhack · « **Reply #77 on:** May 05, 2018, 05:39:46 PM »

Quote from: rsterne on May 05, 2018, 05:10:54 PM

Stainless screws are not necessarily stronger than the stock screws, it depends on the grade of SS....

https://www.gatewaytoairguns.org/GTA/index.php?topic=127914.0

Bob

Thanks Bob. I am well aware, and why I alluded to not having the engineering data.

I meant to ask Travis to qualify what exact kind they were but forgot it amongst the other things we discussed.

PCPhack · « **Reply #78 on:** May 05, 2018, 06:24:29 PM »

I realized this morning that my tanks are all low, and my compressor is not set up. I took one bottle for fill, but their cascades were also low. It will be at least Monday before I can get a full fill and run tuning strings.

dapoun · « **Reply #79 on:** May 06, 2018, 06:07:31 PM »

Sorry if I missed it but what spring setup and hammer are you running at the moment

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Brod build: 100 FPE; stock barrel; shot pic updated

Author Topic: Brod build: 100 FPE; stock barrel; shot pic updated (Read 12545 times))