New shotgun maybe...

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01-25-2009, 04:24 PM
Anonymous D

New shotgun maybe...

I think I may have scratched the revolver, and decided to get a nice tactical shotgun. I realized the only shotty I have is an old Stevens double barrel. And if there was a zombie outbreak, it would be useless. So I need a good pump.

I am liking this one here.

http://www.impactguns.com/store/047700250779.html

I want one just like that EXCEPT I want a 20 in barrel so it will have the longer extension that can hold an extra round. And Ill get a speed fed stock on it. Anyone know where I would be able to buy one already setup like that?
01-25-2009, 09:11 PM
smith357

I just saw an older 20" rifle sight smooth bore 870 express magnum with a top folding stock 3 days ago. It did not have the extension, but it did have the metal trigger group and heavy follower for 200 bones at a local shop .
01-26-2009, 07:54 AM
fm2176

I saw a nice 870P years ago in a gunshop in Staunton. It had a top folding stock, 18" barrel and felt more solid than any other shotgun I have held. I've been wanting one since, but don't want to pay the price of any Remington "P" -series. My Mossberg has a Speedfeed stock. It is over ten years old now and still works great. I've never had a problem with shells coming lose, though they can be awkward to remove if you have clumsy fingers.
02-01-2009, 12:21 PM
bacon ops

Something weird that I've noticed though, is that velocities drop in 20" barrels, for some reason.

I'm not sure if it's just mossbergs, or what, but every time I've seen a velocity comparison between the barrel lengths, there is a drop between 18" and 22"
02-01-2009, 05:33 PM
Syme

Quote:

Originally Posted by bacon ops

Something weird that I've noticed though, is that velocities drop in 20" barrels, for some reason.

I'm not sure if it's just mossbergs, or what, but every time I've seen a velocity comparison between the barrel lengths, there is a drop between 18" and 22"

You probably know that various rifle calibers tend to attain an maximum velocity out of certain barrel lengths, with anything longer or shorter causing a lower muzzle velocity; the same is true of shotguns. Most 12-ga. loads attain full velocity within 12 to 14 inches of barrel, which is why even 10"-barrel breaching guns can get full or near-full performance out of standard ammunition. Anything beyond 14" or so is just lost velocity due to friction with the bore. It's not specific to Mossbergs, it's true of all shotguns. It has to do with the combustion properties of the powder (thus there is some variation between manufacturers and loads), the amount of friction between projectile and bore, and the geometry of the cylinder formed by the bore (closed at one end by the breech and at the other end by the projectile, of course). And it's not that the velocities drop in 20" barrels specifically; velocity starts dropping off well before 20", but for obvious reasons, you rarely see shotguns with barrels under 18" being tested in velocity comparisons. If you did, you'd see that just as 22" barrels get less velocity than 18" barrels, 18" barrels get less than 16" barrels, and 16" get less than 14".

Bottom line, if you want optimum muzzle velocity, go with an 18" barrel--or 14", if you're willing to deal with NFA registration. Not that the lost velocity is particularly significant, though. Definitely less than 100 fps between 14" and 20".
02-01-2009, 05:37 PM
bacon ops

Quote:

Originally Posted by Syme

You probably know that various rifle calibers tend to attain an maximum velocity out of certain barrel lengths, with anything longer or shorter causing a lower muzzle velocity; the same is true of shotguns. Most 12-ga. loads attain full velocity within 12 to 14 inches of barrel, which is why even 10"-barrel breaching guns can get full or near-full performance out of standard ammunition. Anything beyond 14" or so is just lost velocity due to friction with the bore. It's not that the velocities drop in 20" barrels specifically; velocity starts dropping off well before 20", but for obvious reasons, you rarely see shotguns with barrels under 18" being tested in velocity comparisons. If you did, you'd see that just as 22" barrels get less velocity than 18" barrels, 18" barrels get less than 16" barrels, and 16" get less than 14".

mmm, I don't know about that.
02-01-2009, 06:21 PM
Syme

Quote:

Originally Posted by bacon ops

mmm, I don't know about that.

Hahah.. you mean that you didn't know that, or that you don't believe me?
02-09-2009, 11:25 PM
bacon ops

Not about not believing you. I'm sure you think it's true; I just don't know about the physics of it.

the coefficient of friction between lead and steel just doesn't seem high enough for your reason to make sense.

Ahh, yeah, I was right.

http://i98.photobucket.com/albums/l2...e/Velchart.jpg
02-10-2009, 11:04 AM
Syme

Hmm, I've seen conflicting numbers elsewhere. The explanation I gave originally came from Massad Ayoob, I think it's in Stressfire II (the "Advanced Combat Shotgun") one, although maybe from one of his articles. It is strange that velocity drops off so sharply for 20" barrels only on that chart, though.
02-10-2009, 12:07 PM
smith357

Different powder types with different burn rates can greatly effect muzzle velocities from varying length barrels. Basically the slower the powder the longer the barrel needs to be to get the full expansion of gasses. Fast powders work best in short barrels. Typically shot shell powders have a very fast burn rate, magnum powders tend to burn a bit slower and are better with a longer barrel.