Trapshooters Forum banner

1 - 20 of 49 Posts

·
Registered
Joined
·
180 Posts
Discussion Starter #1
Can you guys chime in on this for me please?
What is your opinion on back boring and lengthening the forcing cone in a Perazzi
barrel and the effect it could have on the pattern and velocity.
I had it done on my MX-3 many years ago for recoil but have often wondered
about about how it might have affected the performance of my gun in terms
of velocity and less than desirable patterns....Any advice would be appreciated,
Thanks!......Chee
 

·
Vendor
Joined
·
19,392 Posts
Velocity would be up some, recoil down some, pattern dispersed some. Perhaps more pellets in the 2nd and 3rd rings. Most think more open bores lessen pellet deformation.
 

·
Registered
Joined
·
1,992 Posts
I'd guess with some serious honest pattern analysis you'd be hard pressed to tell any difference. It has however been proven to lighten your wallet a lot more than
recoil.


Jim
 

·
Premium Member
Joined
·
11,728 Posts
According to most physics textbooks, if you remove metal from a gun, and therefore lighten the weight, AND if the said modifications cause, all other things equal, muzzle velocity to increase (and I am not saying it necessarily does) then recoil must go up, not down.
 

·
Registered
Joined
·
10,782 Posts
Take two standard centerfire rifles, Ruger model 77s, one in .270 and the other a .30-06 and both weighed the same with the scopes on them. No changes to the rifles at all from factory specks. Loaded both to the same velocity in fps with a 150 gr bullets. My 06 was a pleasure to shoot all day and my buddies .270 Win. was a hard kicking rifle? Explain?

HAP
 

·
Registered
Joined
·
6,058 Posts
I have an 870TC with a .745" overbored barrel. I think it shoots very soft and everyone who has shot it agrees; some say they can't believe it is an 870. A friend whose 870 would bloody his cheek shot targets in comfort with my barrel on his gun. Accordingly, I have always thought that bigger bores yield less felt recoil.

Some years ago, I sent a KX-5 barrel to a noted barrel guy to have it opened from .730" to .745", the forcing cone lengthened and anything else he usually did including make new chokes for it. When that barrel came back, I shot the gun while changing barrels with an unaltered KX-5 .730" barrel during each post change and felt no difference. In fact, I lost track of which barrel was on the gun at one point. Likewise, shooting three shots on paper from each barrel a couple of times with the same amount of choke constriction in each one showed no obvious difference in the patterns. I didn't count holes and calculate percentages but both patterns sure looked alike so if there was a difference, it wasn't worth worrying with.

So I now subscribe to the belief that the engineers who design our shotgun barrels really do know what they're doing. But that leaves unanswered why my 870 shoots so soft.

Ed
 

·
Registered
Joined
·
3,673 Posts
I always thought that backboring was only good for lightening your wallet but I changed my mind after comparing my TMX to the MX-3 Single barrel that was backbored. Both guns are about the same weight and I believe that the MX-3 has less felt recoil. The TMX shoots very good patterns with the Perazzi chokes and the MX-3 also shoots very nice patterns with Briley Series 54 chokes.
 

·
Banned
Joined
·
2,644 Posts
Your patterns will will run right at 100% from any distance and look like a computer ordered the distribution. Recoil will be reduced to the point that you'll wonder that the gun went off but for the boom.

that's what they tell me anyway.
 

·
Registered
Joined
·
4,155 Posts
Lengthening the forcing cones reduces felt recoil-some, a lot, it depends.

My current Perazzi barrels were reworked by Kerry Allor. The O/U barrels went from .724" to .740:. The unsingle went from .724" to .745". Forcing cone lengths were essentially unchanged. I could discern no difference in felt recoil when I got the barrels back. Patterns, yes. Recoil, no.
 

·
Registered
Joined
·
3,360 Posts
The old barrels with 720-724 bore sure kicked harder to for me the tightness of the bore caused more friction going down the barrel producing more felt recoil for sure. I swiched barrels after two shots to a 740 bore and the difference was easily felt. Ask your self why all the new target guns now have larger bores and longer forcing cones. If yours does not bother you recoil wise leave it alone if patterns are good. Recoil will get to most of us over time so I have recoil devices on most of my break open guns. If Leo used one along with other big dogs why not use what is available I have several PFS and love them but did not buy them for their looks. Seems like the older trap shooters reject the new technology available in todays market. Don't back bore- no porting-no recoil device-no hi ribs-forcing cones should be shortened-da da da


It's 2014 get on the bus or get out of the way

Flame away
 

·
Registered
Joined
·
3,408 Posts
Old One Eye,


"the tightness of the bore caused more friction going down the barrel producing more felt recoil for sure"

How does that increase recoil, felt or otherwise?
 

·
Registered
Joined
·
180 Posts
Discussion Starter #17
Lots of good info, Thanks guys.

I had my barrels re-worked by Kerry at Pro Port back in the mid eighties. But being the lazy ass I was I don't remember if I patterned them after, and if I did, don't remember the results! Shame on me, I know.

I did it to try and reduce recoil for the most part but I do remember Kerry telling me that my patterns would most likely improve and that I "might" gain a little velocity, but don't quote me on the velocity part as that was a long time ago.

I'm just trying to catch up on the tech stuff from the guys on here that know a hell of lot more than I do. I was like a blind rat in a maze back when I shot alot, I'd bump into a wall and turn right or left and try something else.
I appreciate all the info you guys have shared, thank alot!....

One more question...where can a guy get a reasonably priced barrel/bore micrometer gauge? I need to re-familarize myself with my barrels/chokes....Thanks in advance.....Chee
 

·
Banned
Joined
·
2,644 Posts
I think if there were more friction in the barrel then the shot charge would drag the gun away from you.

And I'm way impressed the way that bigger bores can defy Newton's 3rd Law of Motion. We're talkin' some BAD mf'ing juju there!

With wad strippers and big bores I'm surprised that you don't have to hang onto the gun to keep it from being pulled outta your hands.
 
1 - 20 of 49 Posts
Top