NorthernSniper
Well-Known Member
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- Jul 31, 2003
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Polygonal rifled barrels and monometal bullets????
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NS
I did a quick search and didn't find anything relating to Sako and polygonal rifling... I believe the problem with polygonal rifling is not the style (polygonal) but the practice of making the bore a "little tight" so the polygonal system "works" as designed. There are other tight bore barrels around, Palma types I believe are tight .3078 and smaller vice the nominal .308. The bore on the rifles I tried apparently was quite tight too, regardless of rifling type, and this is where I feel the problem begins.
Might try asking some of the Palma type about monometal bullets and observed results. I'd didn't go much further with the quest but if you come across anything please post it.
TIA
[ 01-13-2004: Message edited by: Dave King ]
I did a quick search and didn't find anything relating to Sako and polygonal rifling... I believe the problem with polygonal rifling is not the style (polygonal) but the practice of making the bore a "little tight" so the polygonal system "works" as designed. There are other tight bore barrels around, Palma types I believe are tight .3078 and smaller vice the nominal .308. The bore on the rifles I tried apparently was quite tight too, regardless of rifling type, and this is where I feel the problem begins.
Might try asking some of the Palma type about monometal bullets and observed results. I'd didn't go much further with the quest but if you come across anything please post it.
TIA
[ 01-13-2004: Message edited by: Dave King ]
Nighthawk
Well-Known Member
So if monometal bullets don't work with poly rifling, what do and do you suppose there is a material that is a solid that would work with poly? I remember Warren saying the J40's don't like poly either.
Varmint Hunter
Well-Known Member
Correct me if I'm wrong but I thought polygonal rifle barrels have no lands or grooves. They don't in my poly barreled handguns.
It should be easy to identify a polygonal barrel just by looking into the bore.
I would suspect that polygonal barrels would work best with bullets that are more compressable than the monometal bullets.
Supposedly, poly barrels seal better for minimal gas leakage and are easier to keep clean. Is there an accuracy component to a polygonal rifle barrel?
VH
It should be easy to identify a polygonal barrel just by looking into the bore.
I would suspect that polygonal barrels would work best with bullets that are more compressable than the monometal bullets.
Supposedly, poly barrels seal better for minimal gas leakage and are easier to keep clean. Is there an accuracy component to a polygonal rifle barrel?
VH
VH
There are a couple of types of polygonal rifling as I understand it, most notably "male" and "female". My polygonal rifled barrels look very similar to standard barrels with the exception that there are no sharp edges in the rifling... it looks like worn out standard rifling. The barrels are tighter to afford the better seal and a more compressible bullet would be a good idea. Thinks of a polar bear pulling a seal out of the water through a 4" breathing hole vice a 6" breathing hole... It kills the seal but the 4" "bottle cork" seal gets a little longer and skinnier, bear need to pull a little harder... The larger the projectile I fired through the polygonal barrel the more to the left the group would print, sometimes as much a 6 inches left at 100 yards. This group shifting was repeatable but the reuse of the brass was not as I often blew primer pockets... Polygonal barrels are tight, monometal bullets don't appreciate being reshaped any more than that 4" wide 6' long seal....
There are a couple of types of polygonal rifling as I understand it, most notably "male" and "female". My polygonal rifled barrels look very similar to standard barrels with the exception that there are no sharp edges in the rifling... it looks like worn out standard rifling. The barrels are tighter to afford the better seal and a more compressible bullet would be a good idea. Thinks of a polar bear pulling a seal out of the water through a 4" breathing hole vice a 6" breathing hole... It kills the seal but the 4" "bottle cork" seal gets a little longer and skinnier, bear need to pull a little harder... The larger the projectile I fired through the polygonal barrel the more to the left the group would print, sometimes as much a 6 inches left at 100 yards. This group shifting was repeatable but the reuse of the brass was not as I often blew primer pockets... Polygonal barrels are tight, monometal bullets don't appreciate being reshaped any more than that 4" wide 6' long seal....
littletoes
Well-Known Member
I read a study once that stated that poly barrels foul faster too.
According to a tech rep for one mfgr, poly rifling is inherantly less accurate. It's benifit is in longer barrel life and better performance under sustained rapid fire.
This said, the one I chambered seemed to shoot pretty good. Fouling is significant though.
This said, the one I chambered seemed to shoot pretty good. Fouling is significant though.
Nighthawk
Well-Known Member
If they were that inaccurate I don't think that HK would use it in the PSG1, SOCOM pistols and I don't think Tactical Ordinance would use it in there sniper rifles.
Mikecr
Well-Known Member
Are there any standards w/regard to polygonal rifling? Male, female, rounded lands, flats, octagonal, 6flats, tight, loose, hammered, puttoned, for handguns, for rifles?
I have a Schneider poly(buttoned) that looks as described above, like std 6 lands, only with rounded edges. Gary told me that it would measure the same internal dimensions as any other barrel. I haven't used it yet(bought it for an experiment).
Now, when I was looking around for one, an interesting observation was that ; any maker who offered one, claimed to be the only maker to ever offer them! Like they fail to recognize another makers rifling as polygonal, by their definition.
All I know is that it doesn't look like the rifling in a glock. I can find no other pictures of polygonal.
I have a Schneider poly(buttoned) that looks as described above, like std 6 lands, only with rounded edges. Gary told me that it would measure the same internal dimensions as any other barrel. I haven't used it yet(bought it for an experiment).
Now, when I was looking around for one, an interesting observation was that ; any maker who offered one, claimed to be the only maker to ever offer them! Like they fail to recognize another makers rifling as polygonal, by their definition.
All I know is that it doesn't look like the rifling in a glock. I can find no other pictures of polygonal.
