Another Bulldog question

[YEMX]

Has anyone swapped out the Bulldog's barrel for a TJ 26" twist barrel?  If so, how was the conversion?  What length did you decide on?  O.D.? 

Reason I ask is, I want to shoot cast exclusively (yes, I'm doing other mods...  Longer reservoir, new valve) and an older post Oldpro suggested I go with a longer (32" specifically) barrel.

Anyhoo, I wanted to see if anyone has done this yet.

[YEMX]

Also, for those of you that have opened up your Bulldogs, how much room is there, between the barrel and the reservoir?  Between the barrel and the barrel shroud? 

[FuzzyGrub]

I haven't seen any posts about aftermarket barrels for BD.  It does start with a large OD at breech, then tapers down to a smaller OD.  Not the easiest to do/find.  At one time, was thinking of converting to a smaller cal (.25 or .30). 

I don't have measurements for what you are asking, but there is about 1/4" between barrel and bottom inside of shroud, at the muzzle.  I'd say about 3/8" to air tube. 

For a longer barrel, the shroud will be just for the scope mounting.  I think 32" would extend past the end of the shroud and need a LDC. 

[YEMX]

Hmmm... 

Does the barrel have to taper?  I'm sure Crosman did that just for weight-reduction...  Couldn't one just machine the breech end and the muzzle end for fitment w/the factory parts?

I'm not going to have a huge barrel OD- it is a TJ liner after all. 

Well, I definitely don't want the barrel to extend past the shroud- I'll probably just keep it at 28".  I have a LDC adapter coming from DonnyFl... 

I guess I'm just going to have to get a bulldog sooner rather than later...     

[FuzzyGrub]

Hmmm... 

Does the barrel have to taper?  I'm sure Crosman did that just for weight-reduction...  Couldn't one just machine the breech end and the muzzle end for fitment w/the factory parts?

Yea, it would be heavy if you maintained the OD at the breech, for the whole barrel.  Not familiar with using TJ liners, but when looking at LW .25 or .30. they were not large enough, and would need sleaving.


I'm not going to have a huge barrel OD- it is a TJ liner after all. 


Well, I definitely don't want the barrel to extend past the shroud- I'll probably just keep it at 28".  I have a LDC adapter coming from DonnyFl... 

I guess I'm just going to have to get a bulldog sooner rather than later... 

I agree!
 

[FuzzyGrub]

I did find this:

The problem with replacing the Green Mountain barrel in the Bulldog is that it measures 11/16" for the first three inches, then tapers down to 5/8" over the next three inches.  I checked with TJ and he can't do that.  Trying to sleeve a 5/8" barrel would be difficult as the wall would be just 1/32" thick.  Regards, Tom

From this thread: https://www.gatewaytoairguns.org/GTA/index.php?topic=124304.msg1213367#msg1213367

The LW 357 blank looks to be large enough in OD: http://www.lothar-walther.com/barrel-blank/airgun/standard-profile/90/airgun-blank.357-air-od.71-l-28.03?c=16

[YEMX]

Yeah, I saw that post before...  It's what made me think about not tapering the barrel, just having a larger O.D. and machining down the muzzle and breech ends as needed to fit in the Bulldog...  I'm not too concerned with weight.  I'm really only concerned with whether or not a larger O.D. barrel will fit.  When I get TJ's on the phone, I'm going to have to discuss this with them. 

I'm not going to use a LW barrel, simply because the TJ's 26" twist .357 barrel is a proven shooter with both pellets and cast.  Heck, the one .357 bullet mold I have is designed specifically for the 26" twist barrel...  But I greatly appreciate the time you spent linking the info!! 

[TheLakeRat]

I tried to order one from TJ and he sounded like he would do it and now doesn't seem to want to do it. I just measured and i would not go any bigger than 0.917 on barrel O.D. If you do it will probably touch the shroud.

I'm going to do a caliber conversion when i have time. I've ordered a barrel and will just cut it to fit.

[YEMX]

Man...  I think the only way I can swap the barrel (If I swap the barrel), is I'm going to have to get some 11/16" O.D. steel thin-wall tubing, cut it to the length I need for , and then ream the I.D. to the size I need for a tight slip fit on a 5/8" O.D. barrel.  Or get something with 5/8" I.D. and ream (or hone) to fit the barrel tightly- or perhaps just heat it up and slide it on, once the correct length is cut...  Then machine the O.D. of the sleeved section of the barrel...     Like FuzzyGrub said, that's a thin sleeve... would it be worth it?  Man...  99% of me says yes... 

[Sbak]

What bullet mold do you have that was designed for the tj's .357?

[YEMX]

NOE 357-136-FN.  I still need to send it off to be hollowpointed.

[Ironman482]

Have you thought about tig welding the tj barrel to build up the dia at the breech and then turning it down to fit, if you used at good heat sink and heat dam it would keep warp to a min. And the pressures of Air gun limits are not a factor I  would think, I'm sure others with more knowledgeable than me will chime in hopefully

[TheLakeRat]

Ironman, i've tried that in the past and even with a heat sink on the barrel to stop warpage, you will still get shrinkage of the weld and cause the area that you built up to have a smaller ID than the rest of the barrel.
I think the best option is to machine the sleeve and set it in place with green locktight AKA "bearing retainer" or silver solder and then machine the sleeve down to the correct size to fit into the breech

[Ironman482]

ood info lake rat, haven't seen any post from you on the pitbull in a while, anything new going on , I  installed jsa s balanced vavle in mine, still testing at different  fill pressures and HS settings. So far 3 turns in f rtgom flush and 3200 fill with 142gr NSA I'm getting 4 shots in the 860fps area .that was the best shot string so far good accuracy at 20 yrds .going to test at 50 and 100 soon .

[TroyHammer]

I just modified the valve poppet shape and opened the ports to .300". I added a small reverse coil spring inside the factory spring and at 3400psi I'm getting 3 shots with Nosler 145gr @ 912 average and only 13fps extreme spread. The two follow up shots drop down to 870-880. That's 267fpe average for the first 3 shots. I have a TJ barrel 30" and contemplating sleeving it to fit the breech but want to see how it shoots with the factory barrel at that power first. I'm very happy with the power not really looking for more but if the accuracy isn't there with the factory barrel I'll probably try the TJ barrel.