USFA Lightning copy strength

[medicdave]

Hey all, just wondering what kind of stregth the USFA lightnings have. I'm not familiar with the locking mechanism on the Colt pumps. I'm looking for a companion to my Ruger 45's and would like to be able to feed it the same loads. (Not crazy heavy, but stout. 325's around 1000 to 1100 fps.) Just wanted to hear from someone who knows more about them than I do....Dave

[Hobie]

I would think that they will handle the SAAMI standard and I wouldn't exceed that. That is they aren't Ruger New Model Blackhawk load safe. Of course, that doesn't apply to the .357 mag with its smaller case head. If you want a .45 Colt to load on up there you need a 92 clone.

[medicdave]

Thanks Hobie, what I needed to hear...Dave

[Nate Kiowa Jones]

Hey all, just wondering what kind of stregth the USFA lightnings have. I'm not familiar with the locking mechanism on the Colt pumps. I'm looking for a companion to my Ruger 45's and would like to be able to feed it the same loads. (Not crazy heavy, but stout. 325's around 1000 to 1100 fps.) Just wanted to hear from someone who knows more about them than I do....Dave

The lightning action lockbox works like a chair shoved under a door knob. The locking bolt is hinged off the bottom of the breech bolt and as the action closes the locking bolt drops down and stops at about a 45 degree angle against the lower half of the frame. This lower is somewhat like the trigger plate on a marlin but attached somewhat better.
I know it's not as strong as a 92 or 86. Maybe not even as strong as a 94 or Marlin 336/95 action but it certainly stronger than the toggle guns, 73's, 76's, etc.
I do know that Russel Simpson of AWA-USA did one in 454 Casull but I'm pretty sure he never brought it to market.

[COSteve]

I would think that they will handle the SAAMI standard and I wouldn't exceed that. That is they aren't Ruger New Model Blackhawk load safe. Of course, that doesn't apply to the .357 mag with its smaller case head. If you want a .45 Colt to load on up there you need a 92 clone.

If you're referring to bolt thrust, the higher pressure, smaller case head of the 357mag generates more bolt thrust than a std 45LC but less than Ruger load for 45LC. I believe that equation for bolt thrust is: Case radius² x pi (3.14159) x peak pressure

The 35K psi 357mag's case base = .379" dia, therefore the calculation would be:

.379/2 = .1895² = .0359102 x 3.14159 (pi) x 35,000 (peak pressure) = 3,949lb/ft

The 14K psi 45LC's case base = .480" dia, so it yields:

.480/2 = .240² = .0576 x 3.14159 x 14,000 = 2,5339lb/ft

However, the 25K psi (Ruger load) 45LC's case would generate significantly more thrust:

.480/2 = .240² = .0576 x 3.14159 x 24,000 = 4,343lb/ft

Based upon that, I'd say that the Lightening's action is marginal for the 357mag too.