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I am looking to purchase a HK91 and have come across the the polygonal barrel in the SR9 and Saco HK91's. Does the polygonal barrel add and noticeable accuracy to the gun or is it finicky about ammo?

thanks

Doug
 

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Accuracy? No more than any other quality mass produced barrel. No less, either, though. The two big advantages of the polygonal bore are really higher velocity and extended barrel life. The only ammo concerns I would have would be matching bullet weight to the barrel's twist rate.
 

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For me, the polygonal bore rules....found one for sale locally a year or so ago that went for $2700, sold in like in hour, in the middle of nowhere!!
 

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Accuracy? No more than any other quality mass produced barrel. No less, either, though. The two big advantages of the polygonal bore are really higher velocity and extended barrel life. The only ammo concerns I would have would be matching bullet weight to the barrel's twist rate.
This. The largest developed myth on this board is that polygonal rifled barrels are somehow more accurate... As stated, SOME manufacturers offer it because of the less resistance/more velocity it offers as well as longer barrel life, however standard rifling/button rifling is the standard in ALL match rifles where accuracy is the main concern.

With that in mind, ive also never "shot out" a barrel in any common caliber, so unless your plans are taking it to the 20,000+ round count, id say save your money.
 

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The accuracy issue is a non-issue . HK doesn't use polygonal rifling in all their euro version pistols . It is a less expensive rifling to produce in volume . The main to benefit to me any why it would be good for Mil and LE applications is because the barrel doesn't foul as easy and their easier to clean , no corners to build up lead or copper. You still have to clean the barrel . it's just faster .
 

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The accuracy issue is a non-issue . HK doesn't use polygonal rifling in all their euro version pistols . It is a less expensive rifling to produce in volume . The main to benefit to me any why it would be good for Mil and LE applications is because the barrel doesn't foul as easy and their easier to clean , no corners to build up lead or copper. You still have to clean the barrel . it's just faster .
This as well :)
 

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Accuracy? No more than any other quality mass produced barrel. No less, either, though. The two big advantages of the polygonal bore are really higher velocity and extended barrel life. The only ammo concerns I would have would be matching bullet weight to the barrel's twist rate.
Does someone has trustworthy data on velocity of poligonal vs conventional rifling?
It may be a myth, or not significant at all...

Same wtih barrel life, HK uses high grade steel and cold hammer forging, and these two factors (and not rifling type) may very well be the reson for their claimed long barrel life.
 

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I agree with the high quality of the steel HK uses , that makes a lot of difference in longevity I'm sure . Unless you're loading your own ammo I'd think it would be hard to quantify the velocity . What is the standard deviation of the factory ammo you're shooting ? If I was shooting a full auto gun of any sort , I'd want polygonal rifling . Seems to me the throat would hold up better.
 

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Iirc, the SG1 barrels where rifled?
The polygonal bore was for easier cleaning
and a harder hitting bullet.
 

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I'm not making a blanket statement on polygonal bore barrels in general.....that would be foolish. But the poly barreled HK-91's I've shot, shoot better than any of the conventional rifled HK-91's I've shot (sample size three poly barrels, nine standard barrels).....YMMV but I'm sticking with my experience on this. The real difference seems to be when the barrel gets hot....the poly barrels seems to stay/get tighter, while the standard barrels will start to open up the groups a bit with more flyers. In other words, for a BATTLE rifle, with lots of trigger pulling, I'm leaning on the polygonal bore barrel '91. So glad I have mine. Wish I had another.
 

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Does any maker of MGs use poly barrels? They would use them if they had any advantage for barrel life/POI stability/etc...
 

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I am looking to purchase a HK91 and have come across the the polygonal barrel in the SR9 and Saco HK91's. Does the polygonal barrel add and noticeable accuracy to the gun or is it finicky about ammo?

thanks

Doug
No more accurate with mil surp or handloads than my PTRs...
 
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