.257 Bulldog

[mackeral5]

I am still in the early phases with this one, but so far it is running ok. 1/2" OD 35.5" long TJ's 25-20 barrel sleeved to 19mm with CF. Added Matt's 160cc tube extension for ~500cc of air, IIRC.

The current tune is 7 shots 1023, 1044, 1049, 1052, 1045, 1042, 1028fps, a 7 shot average of 1040fps, 165fpe. 3100psi fill. It uses about 500 psi of air. Bullets are MP Molds 257-640's molded with the deep hollowpoint pin, this batch weighs 68.7 - 68.8gr. At 3200psi and HST dialed up it maxes out at 1125fps with these bullets.



48" long with the Koi, just under 42" in loud mode. Believe it or not the little Koi does a surprisingly good job of knocking the edge off, even at 165fpe.

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Still a lot of work to do, but so far so good.

 

[Metalmaniac]

That thing looks like a lot of fun for varmints. 

 

[dapoun]

Awesome build been following over on the GTA looks a lot more maneuverable than my raptor with a 30 inch barrel .I ordered that same mold it will be here Wednesday cant wait to try it out. Have you slugged the bore and matched a sizer to it? My tj barrel came in at .25695 even after fire lapping and would not shoot .257 sized slugs at all. don't want you to chase your tail like I did.

 

[dyotat100]

Awesome build been following over on the GTA looks a lot more maneuverable than my raptor with a 30 inch barrel .I ordered that same mold it will be here Wednesday cant wait to try it out. Have you slugged the bore and matched a sizer to it? My tj barrel came in at .25695 even after fire lapping and would not shoot .257 sized slugs at all. don't want you to chase your tail like I did.

Then your doing something wrong. Every gun I build I setup to shoot bore size slugs. 



My 257 shoots 257 sized slugs. I can shoot 6 different slugs moa at 100 yards. 

 

[mackeral5]

Awesome build been following over on the GTA looks a lot more maneuverable than my raptor with a 30 inch barrel .I ordered that same mold it will be here Wednesday cant wait to try it out. Have you slugged the bore and matched a sizer to it? My tj barrel came in at .25695 even after fire lapping and would not shoot .257 sized slugs at all. don't want you to chase your tail like I did.

Thanks for the compliments. This barrel started out pretty tight as well, but is a bit larger now after a lead lapping process designed to create a long gentle taper after the lead. Bullets sized at. 257 seem to do ok so far, but it is very early and I have only shot 1 bullet out of it....

 

[Cheplicki]

yep.... thats badass!!!!!!

 

[scallen2112]

I like the look of those slugs. A very "clean" looking cast.

 

[Guest]

Awesome bulldog! Wish I could get my hands on one. 

 

[mackeral5]

Thanks for the compliments. The Bulldog is a very capable platform. The only downside is the crappy clamshell stock.

Over the next week or so I am going to swap to this quick change bolt system. It allows for swapping between .257 and .357 without having to split the stock. Note the long probe pins will be trimmed to length once installed. The .357 barrel is a 1:26 TJ's with probe mounted oring, the .257 is 1:14 TJ's with barrel mounted oring. Both barrels are .500 OD liners sleeved up to 19mm with CF tubing.

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[mercado]

Yup I really don't know why to this date nobody has a custom stock for the bulldog..if varadium air make one I jump on my first bulldog..I asked to pitbull airguns he told me that the trigger mechanism has to be incorporated to the stock..is a simple trigger I don't see a problem there..

 

[mercado]

I don think this stock could be so hard to produce..the Slayer is a bef up bulldog design .. I be good with a stock like this..n the trigger is part of the stock..

 

[mackeral5]

IMO, the Bulldog breech is not robust enough to be setup like a Slayer--with a free floating barrel and scope secured to the breech. The key to Bulldog accuracy is locking the scope down to the barrel. That way any flex at the breech end is immaterial to accuracy. In OEM form, this means better securing the shroud to barrel.

A set of traditional bullpup style barrel bands and scope rail setup would do well on the Bulldog. This system will not be inexpensive to manufacture. Using some parts from the China guns could help control some costs.

For example, I picked up a few P10 trigger assemblies to do something similar, at some point in the future...

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This method would work, but looks a bit odd.

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[mercado]

Yup but just n idea something like this with one more band bolted to the stock it will hold the stock the tube n the barrel in place. 

 

[Ezana4CE]

Yup I really don't know why to this date nobody has a custom stock for the bulldog..if varadium air make one I jump on my first bulldog..I asked to pitbull airguns he told me that the trigger mechanism has to be incorporated to the stock..is a simple trigger I don't see a problem there..

@mercado Not a gunsmith, but I am familiar with the Bulldog’s trigger assembly and linkage. I can’t imagine how it could be dropped into a solid stock. How would you situate the stock trigger assembly into a solid wooden stock?



@mackeral5 Good thread. 

 

[mackeral5]

@mercado-- That is what I had in mind when I said "traditional bullpup barrel bands..." A single screw attaches to the trigger frame, then another towards the butt attaches to the breech. 2 screws to remove the action from the stock vs more than a dozen, lol.



@Ezana4CE--thanks...

There is another member that did a very nice wood stock conversion and he made a custom chassis to utilize the OEM BD trigger/safety system. Here are some pics of the other member's work.

again, not my work, I just saved the pics.

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[mercado]

Dam .. what a change..great looking bulldog..I work with wood, I should have taken the tool n die maker curse..most of those things we want build are not rocket science , with the right tools n some knowledge if you could visualize the part ..everything is doable..I will see if there is a place where I could take a curse on machining. 

 

[Ezana4CE]

@mercado-- That is what I had in mind when I said "traditional bullpup barrel bands..." A single screw attaches to the trigger frame, then another towards the butt attaches to the breech. 2 screws to remove the action from the stock vs more than a dozen, lol.



@Ezana4CE--thanks...

There is another member that did a very nice wood stock conversion and he made a custom chassis to utilize the OEM BD trigger/safety system. Here are some pics of the other member's work.

again, not my work, I just saved the pics.

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That is ****ing gorgeous! 

 

[mackeral5]

Slowly creeping up on a regulated tune. A full fill of 3500psi, Huma maxed out at 175bar, 15 shots averaging 970fps with MP 257-640's weighing 69.3-4 gr.

15 shots at 50 yards

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Then stretched out to 102 yards. Bottom target was used for sighters. Top target is 5 shot groups. Top left bull was shot with 5 shots fed from the magazine.

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Geo Schoonmaker designed and printed the magazine wheel. I added a .050 shim to the bullet stop in the OEM mag to make up for the difference between .357 and .257

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The slot cut in the rear of the magazine is due to my running a slightly longish pin probe, not required for converting a magazine to .257....



In unregulated form, with a long 500cc high pressure tube and filled to 3500psi, it will send an 88gr "lovern" style slug in the 1120's, over 240fpe... I have an Arsenal 85gr mold on order, hopefully it gets here before easter. With a softer, lower friction bullet I believe it may break 250fpe maxed out.

 

[mercado]

Nice a 55" gun is not needed to make good speed..awesome