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View Full Version : p7 Barrels- polygonal type ?

eddyfinster
06-08-2008, 07:25 PM
Does any one know what kind of barrels the p7 police trade ins are. I know they are polygonal, but i have other pistols with polygonal rifiling and they dont look the same. My p7 barrel looks very shiny inside with smooth soft looking land and groove, very rounded almost. Not like my others where the lands and grooves are sharp and square looking. Or is this just my p7 with a worn out barrel.
ripley16
06-09-2008, 02:13 PM
Not sure what your question "Does any one know what kind of barrels the p7 police trade ins are" is asking. Your P7 should look like this;
http://i72.photobucket.com/albums/i186/ripley16/P7Chamberandbarrel.jpg

Not all polygonal barrels look alike, just as not all land and groove barrels are not the same.
eddyfinster
06-10-2008, 12:57 AM
Not sure what your question "Does any one know what kind of barrels the p7 police trade ins are" is asking. Your P7 should look like this;
http://i72.photobucket.com/albums/i186/ripley16/P7Chamberandbarrel.jpg

Not all polygonal barrels look alike, just as not all land and groove barrels are not the same.

Thanks for the pic i really appreciate it. My p7 barrel just didnt look like any of my other barrels inluding my USP. I just didnt know if the lands and grooves were supposed to be as rounded as the p7 barrel is. With the roundness and softness of the barrel twists i thought my barrel was worn out. Thanks again for the pic.
AviatorDave
06-10-2008, 02:42 AM
Thanks for the pic i really appreciate it. My p7 barrel just didnt look like any of my other barrels inluding my USP. I just didnt know if the lands and grooves were supposed to be as rounded as the p7 barrel is. With the roundness and softness of the barrel twists i thought my barrel was worn out. Thanks again for the pic.

If you see sharply defined lands and grooves, then it's not polygonal rifling. Not all USPs have polygonal rifling, I think they switched to polygonal rifling in the mid-1990s.
eddyfinster
06-10-2008, 02:45 AM
If you see sharply defined lands and grooves, then it's not polygonal rifling. Not all USPs have polygonal rifling, I think they switched to polygonal rifling in the mid-1990s.

Im confused then. My USP was made in 93,the first year they made them, I thought it was polygonal now im not sure, how can you tell the difference, and what is the differance
AviatorDave
06-10-2008, 03:10 AM
Im confused then. My USP was made in 93,the first year they made them, I thought it was polygonal now im not sure, how can you tell the difference, and what is the differance

Nope, 93 USPs were not polygonal. They are land and groove. The change was made in 1994 or 1995. Below is a cross-section view of each style of rifling. Note that not all polygonal rifling has such large radius transitions however. Some has much better defined peaks, but if there are smooth radii between the major and minor diameters, it's polygonal. If there are sharp angles, it's land and groove. But HK's version of polygonal always looks like the view on the right with very smooth transitions.

http://upload.wikimedia.org/wikipedia/en/f/f8/Polygonal_vs_normal_rifling.gif
eddyfinster
06-10-2008, 03:21 AM
thanks, i like the diagram
AviatorDave
06-10-2008, 03:25 AM
thanks, i like the diagram

And this is on the HKPro World of HK page, and the November timeframe is probably why I've seen some reports that the change was in 94, and some in 95:

In November, 1994 the barrel was changed from conventional land and groove to polygonal bore profile.
P7M8_P7M13
06-10-2008, 06:04 AM
As far as I know that all P7 series pistols have polygonal barrels except P7M10.
AviatorDave
06-10-2008, 07:31 AM
As far as I know that all P7 series pistols have polygonal barrels except P7M10.

I have two manuals, one is much older than the other. They don't differentiate barrel types, it just says "P7 pistols have a hammer forged polygonal barrel", which would lead me to believe that the M10 has the same polygonal barrel.

Is that not correct? Does the M10 in fact have a land and groove barrel?

I know of at least one glaring error, so this could be one too. The errror? In a table of specifications of the different models, under the P7M10 column they list the caliber as 9mmx19. Doh!
cueist
06-10-2008, 09:42 AM
The P7M10 barrel is polygonal.
JoeyBones
06-10-2008, 05:22 PM
I could have sworn that the M10 was conventionally-rifled. All examples I've come across definitely seemed to be very differently profiled than the polygonal barrels of my other P7's (As in land & groove?)...

Regardless, I've always considered the M10 to be the red-headed step-child of the P7-series - So they don't count anyways... lol... j/k guys...

Regards,
-Bones
cueist
06-10-2008, 08:24 PM
I could have sworn that the M10 was conventionally-rifled. All examples I've come across definitely seemed to be very differently profiled than the polygonal barrels of my other P7's (As in land & groove?)...

Regardless, I've always considered the M10 to be the red-headed step-child of the P7-series - So they don't count anyways... lol... j/k guys...

Regards,
-Bones



My mistake, upon further research (the big red book) the P7M10 had 6 lands and 6 groves.

For some reason I thought that it was the P7M7 that had the lands / groves barrel.
ripley16
06-10-2008, 10:35 PM
I didn't know that either (about the M10).., nice to learn something new.
Nra-life-member
06-11-2008, 04:42 AM
My mistake, upon further research (the big red book) the P7M10 had 6 lands and 6 groves.

For some reason I thought that it was the P7M7 that had the lands / groves barrel.


Wish we had P7M7's so we could compare and chat about them..
BytorJr
06-12-2008, 05:33 AM
Since we're on the topic of polygonal barrels.

How many sides do the HK's have? I know glocks are 6 sided (hexagonal) so I'm assuming HK's are probably more. Glocks almost look like they have a wee bit of land and groove to them; whereas HK's seem to be almost smooth. I'm guessing 8 sided (or octagonal) in shape.

Thanks.
AviatorDave
06-13-2008, 02:32 AM
Since we're on the topic of polygonal barrels.

How many sides do the HK's have? I know glocks are 6 sided (hexagonal) so I'm assuming HK's are probably more. Glocks almost look like they have a wee bit of land and groove to them; whereas HK's seem to be almost smooth. I'm guessing 8 sided (or octagonal) in shape.

Thanks.

P7s and USCs have hexagonal polygons, and I'm not going to drag my SR9T out, but I think it's also 6 sides.