Author Topic: A 25 Cal Fortitude (Read 8420 times))

FuzzyGrub · « **Reply #80 on:** January 26, 2019, 07:35:56 PM »

The Disco/Maximus is 2", while the Prod is 1.25". I think it estimated out at 5cc per inch. I have a prod gauge block somewhere in the drawer, if you need the length of that.

mackeral5 · « **Reply #81 on:** January 26, 2019, 08:07:40 PM »

Quote from: FuzzyGrub on January 26, 2019, 07:35:56 PM

The Disco/Maximus is 2", while the Prod is 1.25". I think it estimated out at 5cc per inch. I have a prod gauge block somewhere in the drawer, if you need the length of that.

Thanks for the info. Length on the Prod gauge block won't matter. I seem to recall it being just over 1". Now that I have the extra capacity of the double tube I may just go with the Disco plenum and add it to what I've got now, which is around 15 or so cc I believe.

FuzzyGrub · « **Reply #82 on:** January 27, 2019, 01:56:24 PM »

I have been chasing a persistent slow leak. I ignored it for a while, because was tearing it back down, during the tuning process. The leak was coming from the trigger assy hole, so it had to be something with my plenum spacer. Initially, I thought I didn't get a good seal with the brass plug with the epoxy, but found I was taking a small chunk of the o-ring out as it passed the gauge hole and trigger hole. Deburred these holes again, and put extra care in depressing the O-rings as they were pushed past the subject area. Still leaked.

I think I finally found it. The plenum spacer was made from a special gauge block that was given to me. On this bock, the 113 o-ring grooves had a depth of 0.600". Comparing to the Fortitude gauge block which read 0.590". Checked the Prod and a Maximus block, and found the same 0.590". This was making the O-rings tighter than needed and was enough that I kept scalping the O-rings.

So, made a new plenum spacer from the Fortitude one. It is exactly the same length as my "special" one, so the spacers all stood the same. Note that the Fortitude gauge block is not flat. If you plan on sealing a huma plenum against it, it would need to be flat sanded. I'm going to keep using the Prod gauge block, seeing how I have enough air volume to meet my goal. I drilled out the main passage to 3/8". Filed down the top of the brass plug to get it to fit below the surface. Epoxied it last night and installed this AM. So far, so good.

My original spacer on the left, Fortitude one on right.

mackeral5 · « **Reply #83 on:** January 27, 2019, 06:01:16 PM »

Quote from: FuzzyGrub on January 27, 2019, 01:56:24 PM

I have been chasing a persistent slow leak. I ignored it for a while, because was tearing it back down, during the tuning process. The leak was coming from the trigger assy hole, so it had to be something with my plenum spacer. Initially, I thought I didn't get a good seal with the brass plug with the epoxy, but found I was taking a small chunk of the o-ring out as it passed the gauge hole and trigger hole. Deburred these holes again, and put extra care in depressing the O-rings as they were pushed past the subject area. Still leaked.

I think I finally found it. The plenum spacer was made from a special gauge block that was given to me. On this bock, the 113 o-ring grooves had a depth of 0.600". Comparing to the Fortitude gauge block which read 0.590". Checked the Prod and a Maximus block, and found the same 0.590". This was making the O-rings tighter than needed and was enough that I kept scalping the O-rings.

So, made a new plenum spacer from the Fortitude one. It is exactly the same length as my "special" one, so the spacers all stood the same. Note that the Fortitude gauge block is not flat. If you plan on sealing a huma plenum against it, it would need to be flat sanded. I'm going to keep using the Prod gauge block, seeing how I have enough air volume to meet my goal. I drilled out the main passage to 3/8". Filed down the top of the brass plug to get it to fit below the surface. Epoxied it last night and installed this AM. So far, so good.

My original spacer on the left, Fortitude one on right.

I am planning to use a Prod gauge block, thanks for the heads up.

FuzzyGrub · « **Reply #84 on:** February 10, 2019, 05:22:00 PM »

FWIW: While I was able to fix my leak at the plenum ext, still have a slow leak unable to locate. I couldn't find it with suds/foam and did a couple of re-o-ring and re-taped the foster. Kicking my ^&*.

Need to go to full submerge on air tube.

mackeral5 · « **Reply #85 on:** February 10, 2019, 08:38:29 PM »

Quote from: FuzzyGrub on February 10, 2019, 05:22:00 PM

FWIW: While I was able to fix my leak at the plenum ext, still have a slow leak unable to locate. I couldn't find it with suds/foam and did a couple of re-o-ring and re-taped the foster. Kicking my ^&*. Need to go to full submerge on air tube.

Some leaks are tough..... My Huma QB78 needs a reg rebuild, ever so slight leak out of the vent that persists after 2 teardown/oring replacements.

BTW, I finally used my GM .25 barrel. Some time ago I had ordered the parts to make a complete spare barreled action for my P15. Now I have .25 and .22 barreled actions but only have one stock LOL... I found the GM barrel to have a very tight choke, very much like what you found in this thread. I worked on it a bit with bore paste and that helped some but it is still pretty tight. I still have to thread the muzzle, when I tear down for that I plan to spend some more time working on the choke.

FuzzyGrub · « **Reply #86 on:** August 05, 2019, 06:16:29 PM »

I got a Boyd's AT-ONE stock that will fit my three long tube prod/fortitudes, from a GTA member. I tried it on my 25 cal Fortitude.

It joins a Blaster, Varmint Thumbhole, and syn stocks.

FuzzyGrub · « **Reply #87 on:** December 15, 2019, 05:27:44 PM »

I picked this back up, after a long hiatus. I was plagued by a slow leak that I couldn't find, via aersol leak detector on all the possible locations. I gave the air tube a warm water bath, and was able to quickly find it. It is leaking from the gauge vent hole. Which is not uncommon, but I had been hitting the back side of the gauge, and this one was on the outer perimeter.

This was a new gauge from MC, too. Anyway, glad to find it. All along I was worried that it was coming out the reg vent, which could mean anywhere within my large stack of parts for the plenum.

Going to fix the stock lug. A couple of members have pointed me to Lloyd's article: https://www.gatewaytoairguns.org/GTA/index.php?topic=41405.0 and have discussed their success using it. I had something more elaborate and more problem prone in mind.

The barrel for this, came from my Mrod, and was replaced with a new one. That turned out to be a crosman barrel, while this one is GM. This is going back in the Mrod, and a new crosman barrel will be ordered on Monday. The original replacement went into the 25 Liberty project. None of the modifications to the barrel, up to this point, effected its use in a Mrod. I do plan to machine the front edge of the barrel to 7/16" from the 1/2", so that it will be able to use the stock Seneca Aspen 25 mags. Making one custom mag was fun, making a few more, just seemed like work.

The hammer in the Fortitude (same as Disco/Maximus) has allot of material between the face and back of spring pocket. Going to drill a pocket and add some peek to reduce some of the mechanical noise.

FuzzyGrub · « **Reply #88 on:** December 16, 2019, 11:21:50 AM »

Ordered the 25 Mrod barrel, current price is $62.30

I was able to get the CS rep to look up a Fortitude air tube, since mine is scratched up from all the times assembled/disassembled, only $24.24

FuzzyGrub · « **Reply #89 on:** December 16, 2019, 12:26:59 PM »

Quote from: FuzzyGrub on December 16, 2019, 11:21:50 AM

Ordered the 25 Mrod barrel, current price is ~~$62.30~~

I swear that is what I heard, but the email invoice shows: Barrel, .25 cal. 2563-001 $46.73

I was able to get the CS rep to look up a Fortitude air tube, since mine is scratched up from all the times assembled/disassembled, only $24.24

Price correction: Barrel, .25 cal. 2563-001 $46.73

Air Tube: ME-013 $24.25
Barrel Band: ME-008 $6.35

subscriber · « **Reply #90 on:** December 16, 2019, 01:21:32 PM »

Dare I say Crosman's parts are reasonably priced (yes, free would be nice, but that is not realistic).

I see the Crosman .25 barrels is a lot cheaper than what they sold the GM barrel for a year or so ago. That was $75, if I recall.

Buldawg76 · « **Reply #91 on:** December 16, 2019, 01:33:43 PM »

Quote from: FuzzyGrub on December 16, 2019, 12:26:59 PM

Quote from: FuzzyGrub on December 16, 2019, 11:21:50 AM
Ordered the 25 Mrod barrel, current price is ~~$62.30~~

I swear that is what I heard, but the email invoice shows: Barrel, .25 cal. 2563-001 $46.73

I was able to get the CS rep to look up a Fortitude air tube, since mine is scratched up from all the times assembled/disassembled, only $24.24

Price correction: Barrel, .25 cal. 2563-001 $46.73

Air Tube: ME-013 $24.25
Barrel Band: ME-008 $6.35

That's odd that they would keep the same Gen 1 part number of 2563 for the new non GM 25 cal barrel since I would think it would be easier to be able to differentiate between the two parts. But then if the GM is no longer available it likely does not matter now.

BD

FuzzyGrub · « **Reply #92 on:** December 17, 2019, 06:46:02 PM »

Received UPS email that the parts will be arriving tomorrow.

So tore down the pressure tube. I will be giving the original Fortitude air tube away, just pay shipping. It has a few scars, but nothing terrible. If interested, keep eye on classifieds.

mackeral5 · « **Reply #93 on:** December 17, 2019, 08:17:36 PM »

thanks for sharing the new barrel price----that price is hard to beat for transplants/conversions. I need to pick up another for my stash.

FuzzyGrub · « **Reply #94 on:** December 18, 2019, 03:13:15 PM »

Well, received the parts order today. Guess what is on back order? …. yep, the barrel.

At least I have the air tube and gauge to get the bottom end back together.

TF89 · « **Reply #95 on:** December 19, 2019, 11:51:07 AM »

Darn, too bad about the barrel. Glad to hear that it is coming together. Reading your story has made me appreciate that I have not had any major leaks other than the normal ones of cutting the o-rings during assembly.

FuzzyGrub · « **Reply #96 on:** December 19, 2019, 04:30:06 PM »

Quote from: TF89 on December 19, 2019, 11:51:07 AM

Darn, too bad about the barrel. Glad to hear that it is coming together. Reading your story has made me appreciate that I have not had any major leaks other than the normal ones of cutting the o-rings during assembly.

I think John (Crosman_Engineer) made improvements in G2 to minimize leaks. The G2 I received recently, doesn't have any issues with leaks. Rock solid.

Just received a UPS shipping notice. Looks like the barrel (only thing back-ordered) will be here tomorrow.

FuzzyGrub · « **Reply #97 on:** December 20, 2019, 09:00:06 AM »

Assembled the air tube. It did take a couple of times on the thin valve O-rings to get past the gauge and screw hole unscathed. The edges are not as sharp as Gen 1 tubes, and I didn't dress them before install. I did notice a new regulator vent hole. Gen 1 relied on the thread gap between the tube and stock lug. I pressurized to just under 2K last night, and still there this AM.

Will keep an eye on it for next few days.

As luck would have it, the barrel is now showing a Monday delivery.

I'll work on the peek striker and have the complete lower assembly done before it arrives.

The regulator came for the Liberty, so now its waiting on the Fortitude.

mackeral5 · « **Reply #98 on:** December 20, 2019, 12:13:39 PM »

Congrats on the no leaky! Sometimes that can be a challenge on our regulated guns (more orings and opportunities to damage them.)

FuzzyGrub · « **Reply #99 on:** December 26, 2019, 04:50:37 PM »

The crosman 25 cal barrel did arrive.

Definitely a crosman, 7 lands, not GM. I pushed a few JSB's through it, and found it just like the previous, with a very tight choke. I did not find any burrs that were taking chunks out of the pellet. No visible issue with rifling. Barrel was relatively clean, too. Installed it in a mrod. Groups were single pellet hole at 10yds and consistently hitting 1" spinners at 50yds. Declared the accuracy good enough to start the machining, which voids the 30 day warrantee. Also, the leade, like the other one, chunky on probe closed.

This will go on the caveman lathe to turn down the very first 0.060" to 7/16" from 1/2", so the standard Seneca aspen 25 cal mags will fit. Otherwise, the same machining I did before:

- Side clearance for the two breech screws
- TP to 0.187"
- Smooth leade
- Flat for new shroud mount location

After 6 days, gauge hasn't budged, so declare it leak free.

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A 25 Cal Fortitude

Author Topic: A 25 Cal Fortitude (Read 8420 times))