Tuning bulldog

I see a lot of user with this problem. Slugs are not like bullets and the manufacturer should stop using generic 357 or 45 calibers in the description. I have a Hercules Bully that was labeled 45 cal. Most 45 cal slugs are .457 and are to big for this gun. The correct caliber is .454. Make sure your ordering the right size. 357 slugs can be .356, .357, or .358. I picked up a good dial caliper and double check the size of a couple of each in every new purchase because people make mistakes.

Like the above mentioned, that pressure didn't go out the barrel so it is likely you blew an o-ring. You have one of the best guns for after market parts.

I prefer ProSlugs.com as he only carries big bore. He also offers to Nano Silicon Coat your slugs for $3 or Alox Bullet Lube them for $5. Bullet lube can help prevent a slug from getting stuck in the barrel. Also these are hunting slugs and intended for killing, not target practice. These may not shoot the tightest grouping but tear a hole thru whatever they hit with the greatest expansion and blood loss.
 
My bulldog shoots bullets up to .359.

It favors. 356

Check the barrel for a jammed bullet.On low pressure I got a. 358 stuck.Perhaps you have a Buller stuck.Once mine blew air out the bolt probe that oring never sealed once the blockage was removed.

I shoot hard cast 380,9mm,357 and .38 pistol reloads with no issues.I now resize them all to .357.
 
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this is a .358 and a 50 yard un tethered 5 shot group.

148 grains at 880 feet per second.