Bulldog modification log .328 porting and more

[ShakySarge]

Only this issue remains. It's a little too long and hits the breech plastic cover near the gauge. This only prevents a tiny bit of the bolt retraction, so might not matter. I will probably just grind it down a little to clear the bump.

If you want, I can send you a new one. If you wish to just grind it a bit I am okay with that too. As I stated before, I would have never thought about the idea had it not been for your input! I agree that it makes the cocking sooooo much smoother and the lock up of the sear is crisp and easy compared to the bending piece of aluminum we were given from the factory!

[PCPhack]

I'll just see if grinding it is enough Matthew. Thanks!

[PCPhack]

Since the ideas are flying, how about a MDS hammer, with adjustable striker? As the factory striker goes down into a smaller circumference, recessed opening than the hammer itself down inside the breech, having an adjustable striker with a MDS hammer would give a buffer adjustment as well. I would buy one instantly Travis.

A bit off topic, but I am real close to ordering a Slayer 452, and if I get my hands on that will probably lose Bulldog interest. It could mean missed sales for JSAR if the parts come too slow. Hint, hint.   

[ShakySarge]

Since the ideas are flying, how about a MDS hammer, with adjustable striker? As the factory striker goes down into a smaller circumference, recessed opening than the hammer itself down inside the breech, having an adjustable striker with a MDS hammer would give a buffer adjustment as well. I would buy one instantly Travis.

I was thinking along the same lines. Possibly a Stopping Spring Guide is feasible?

[PCPhack]

I have decided to have my custom length titanium reservoir not be any longer than where the actual barrel muzzle ends (actual barrel, not the shroud). There are a few reasons for this. The Pitbull reservoir is a bit longer, and mates up nicely to where their moderator ends. However, a longer reservoir means that only a very short moderator, like the Pitbull, will fit. I just noticed this morning that the 3d printed Pitbull moderator has chipped off. This one has maybe 100 slugs through it since I received it, and it itself was an exchange because the first one threw off my POI. I am sure they would exchange it again, but I will go back to my DonnyFL moderator. The DonnyFL one also screws off easier, if I want to shoot bolts. The second reason for a reservoir not to surpass the end of the barrel, is that I might some day switch the shroud out, and go with something else (come on JSAR). I don't want potential interference from the reservoir.

[Lani52]

Fascinating thread.

I ported mine to the original .277 that Tkerrigan had recommended, I have a new .30 bit, but when  Tom K bored his out to .30 while testing some bullets for me, he only picked up less than 5 FPS.

I agonized also about that Tii tube length.  I have two uppers, the original one is the .277 and has a short Pitbull on it.  The second has the mega on it and both are glued on, a blow torch would be needed to remove them.  I have broken a Pitbull once while removing it and I am hoping it will extend the life.   Having said that, if the mega fails, I may just cut the barrel back to 22 inches so I can fling arrows with it.

Roachcreek

[PCPhack]

I am thinking to go 24 inches on the titanium reservoir. That leaves about 1.75 inches of barrel beyond it (~1.5 with endcap), to accommodate a tensioning nut if I ever decide to do such a modification. It also leaves a bit of rail space on the factory shroud if I want to use it. Without any better input about future mods, that is the best compromise that I can think of. This will give around 385cc (389 with straight linear math of tube sizes scaled from factory claimed spec, but I believe it's closer to 385).

Other tube lengths for reference:
Factory: 20 31/32 inches (20.96875)
Pitbull: 30 7/32 inches (30.21875)
Note these are tube lengths, not including any end caps.

[PCPhack]

Fascinating thread.

I ported mine to the original .277 that Tkerrigan had recommended, I have a new .30 bit, but when  Tom K bored his out to .30 while testing some bullets for me, he only picked up less than 5 FPS.

I agonized also about that Tii tube length.  I have two uppers, the original one is the .277 and has a short Pitbull on it.  The second has the mega on it and both are glued on, a blow torch would be needed to remove them.  I have broken a Pitbull once while removing it and I am hoping it will extend the life.   Having said that, if the mega fails, I may just cut the barrel back to 22 inches so I can fling arrows with it.

Roachcreek

There are indeed diminishing returns on going larger with the port. The bolt begins to be in the way for increased flow, unless you also start modifying the bolt.

I should receive my titanium tube by Christmas.

I have some Air Venturi bolts, but have not tried them out yet. It is easy enough to pop off the moderator and front piece to test, but I just haven't gotten to it yet. I hope to try them this coming weekend.

[FuzzyGrub]

I think mine was 26.5" to keep it just short of the barrel, with the added airbow fill port and gauge.

If you are doing the airbow fill and gauge, the 2.5" for a short rail is probably not worth it.  Anything there would block reading the gauge.  A few more inches of airtube might better for you. 

[PCPhack]

I think mine was 26.5" to keep it just short of the barrel, with the added airbow fill port and gauge.

If you are doing the airbow fill and gauge, the 2.5" for a short rail is probably not worth it.  Anything there would block reading the gauge.  A few more inches of airtube might better for you. 

I think that you didn't follow my logic. I chose 24 inches to make the reservoir end behind the actual barrel end, not the shroud end. I might be ditching the shroud all together in the future for a tensioned barrel and cantilevered rail. As such, I wanted to plan ahead now by not having a tube that is too long. In the meantime, with the factory shroud, it allows quite a bit of bottom rail still, if I want to use it. I am not planning to use the airbow fil port, although I do have one.

[Lani52]

Could your quest for a longer travel on your bolt be responsible for the Wear your seeing?

I played around with three different generations of Tagdaggers’arrow  conversion on the AF Condor, it was hard to cock, really rough on arrows and so deadly accurate, it turned a pellet shooter into a weapon that could be used to humanely take any animal on the planet. The offshoot of Tagdaggers product was that you got to deal with Tagdagger, a finer gentleman than Dave is hard to find these days.  However, the Bulldog/JSAR valve/Air venturing combo is far more user friendly than the Condor platform as you can use bullets or arrows interchangeably.

Roachcreek

[PCPhack]

Lani, the bolt hole wear existed long before I started modifying the bolt travel. It is also a factor for non modified Bulldogs over time. You will even note that Pyramyd stocks them, but not all Bulldog parts. I am guessing it is because people are looking for them when their original starts wearing out.

[FuzzyGrub]

I missed barrel vs shroud.  The airbow fill/gauge won't fit the standard BD tube threads, which I assume JSAR is providing.   Is the plan to use a short piece of the shroud for scope mount or doing something more custom to mount to receiver? 

[PCPhack]

I missed barrel vs shroud.  The airbow fill/gauge won't fit the standard BD tube threads, which I assume JSAR is providing.   Is the plan to use a short piece of the shroud for scope mount or doing something more custom to mount to receiver?

I would guess no factory shroud at all, but a rail mounted back to the breech cantilever style, like a Slayer. Speaking of which, I may end up leaving the Bulldog as is shroud wise, calling it done after the titanium reservoir, and getting a Slayer .452. Then I would just use the Bulldog for when stalking around on the ground. I am waiting a bit to be honest to see what JSAR will release. I have a few projects ongoing, so will let someone else be the guinea pig on that one.

[PCPhack]

A small bit of test feedback on my grinded out bolt, custom linkage, and metal cocking lever is that without the rear plastic on, the lever can drop a little more, which retracts the bolt maybe another half millimeter. The difference is 8 to 10 fps compared to the plastic on. So there is still some power to be had even after the grinding that I did!

Michael, want to try to make another lever, with the nub that the dogbone link attaches sticking out another 3/16" further compared to stock? That would give the little extra retraction and should not hit anything.

[Coyote]

Could your quest for a longer travel on your bolt be responsible for the Wear your seeing?

I played around with three different generations of Tagdaggers’arrow  conversion on the AF Condor, it was hard to cock, really rough on arrows and so deadly accurate, it turned a pellet shooter into a weapon that could be used to humanely take any animal on the planet. The offshoot of Tagdaggers product was that you got to deal with Tagdagger, a finer gentleman than Dave is hard to find these days.  However, the Bulldog/JSAR valve/Air venturing combo is far more user friendly than the Condor platform as you can use bullets or arrows interchangeably.

Roachcreek

I went through three without having modified a thing. I've noticed that quite a few people seem to believe that this problem is only caused by modifying the Bulldog. Well, that's all I have to say for now.

[Lani52]

Knowledge is power, thanks guys.   I probably have not shot mine enough to show any wear.

Perhaps I will see if I can have a stock form of the bolt made of steel.

Roachcreek

[ShakySarge]

A small bit of test feedback on my grinded out bolt, custom linkage, and metal cocking lever is that without the rear plastic on, the lever can drop a little more, which retracts the bolt maybe another half millimeter. The difference is 8 to 10 fps compared to the plastic on. So there is still some power to be had even after the grinding that I did!

Michael, want to try to make another lever, with the nub that the dogbone link attaches sticking out another 3/16" further compared to stock? That would give the little extra retraction and should not hit anything.

Should be able to get it done and would only need to switch up the template used. Would you be saying 3/16” more towards the muzzle end or more towards the other side of the receiver?

[ShakySarge]

I suspect towards the muzzle at it would push the bolt just a little further in.

[ShakySarge]

Perhaps this image will help. Towards the thin line or the fat one?!