RAW BM500 Polygonal vs cut rifling barrel
- Thread starter mubhaur
- Start date
No, no, no. Let me change my story. The first RAW I owned was an HM1000 LRT that I bought used. I found out that it was built specially for a customer who supplied a CZ barrel because he like them on Cricket rifles. I just looked through my records. In those days, these rifles were tuned to shoot 18.1 gr pellets around 850 fps. As I previously said, this gun shot ok, but nothing to write home about. I sold it.
NOW, I did buy another HM1000X from a friend who bought it with the custom Benchmark barrel option, and that rifle did shoot well. Velocity on that one with 18.1 gr pellets was 895 fps. That's the one that got the wink. Benchmark barrels are rather scarce and I think Martin didn't want to go that route and built custom options. Just guessing. Good thing I keep records cause at my age, my memory bank is full. I've owned a lot of airguns so, it's hard to remember all the data.
NOW, I did buy another HM1000X from a friend who bought it with the custom Benchmark barrel option, and that rifle did shoot well. Velocity on that one with 18.1 gr pellets was 895 fps. That's the one that got the wink. Benchmark barrels are rather scarce and I think Martin didn't want to go that route and built custom options. Just guessing. Good thing I keep records cause at my age, my memory bank is full. I've owned a lot of airguns so, it's hard to remember all the data.
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Man, I wish I could get a cut rifled barrel for my RAW .22cal. I got 2 poly barrels from Martin and they both shoot like garbage. I was talking with him about it and he said that they have been this way for years. It looks like I'll need to have one machined or go up to .25cal 
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It's very strange if Martin advised you that in .22 the LW polygonal barrels are not good.Man, I wish I could get a cut rifled barrel for my RAW .22cal. I got 2 poly barrels from Martin and they both shoot like garbage. I was talking with him about it and he said that they have been this way for years. It looks like I'll need to have one machined or go up to .25cal
RAW has been continuously using polygonal barrels in their .22 guns.
How can Airforce and RAW afford to sell the guns with known accuracy issues !
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Cut rifling any day. Hammer forging accumulates a lot of stress in the steel. Button rifling less but still. That issue can be resolved with proper annealing but I am yet to see an airgun barrel which was properly annealed. Hammer forged barrels close when one reduces its outer diameter, whereas button rifled barrels open up.
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In the beginning, poly barrels were used because they did not foul as easily.They were not used in air guns...in the beginning, pistols.
There are barrel makers you will never hear of.
Most accurate, talking really accurate will out shoot the shooter,the barrels are tested in a jig.They must pass ,no shooter is as accurate as a jig.Where lies
the problem.
There are barrel makers you will never hear of.
Most accurate, talking really accurate will out shoot the shooter,the barrels are tested in a jig.They must pass ,no shooter is as accurate as a jig.Where lies
the problem.
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Wow,That is a new one for me;I certainly would take their word,I have to check out why now.,I believe it was the German pistol maker that introduced the poly barrel.....that was like 30 or so years ago.....maybe I am outdated,anyhow I am going to update my education on such matters.
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When it comes to polygonal rifling, "faster shooting", and "reduced fouling" are marketing speak for cheaper to manufacture. Polygonal rifling makes as much sense to spin a bullet as does rounding off the corners on a hex nut so you can torque it properly.
If you want a spline to work, you need more surface area that is close to perpendicular to the force you are applying in order to generate torque. Very shallow contact angles basically more easily crush the softer of the two materials in contact. When it comes to lead bullets in a Glock, the poly rifling lands crush the bullet and open a gap on the other side of the "land". This allows excess hot gas to leak past the bullet, melting some lead at those gaps and soldering it to the barrel. The very opposite of less blowby and reduced fouling.
Now, there are several styles of polygonal rifling, and my fundamental objection is not equally strong for all of them. Lead pellets are light for caliber, and cold air is not going to melt the lead. So poly barrel may work fine for airguns; but that is not the same as superior to conventional rifling for pellets or slugs. The exact style, dimensions, consistency and finish matter a great deal.
In the same way, conventional spline rifling, whether cut, button rifled, broached or hammer forged also come in many different styles and depths. And the quality and consistency down the barrel is not related to the style of rifling, but by the cost and care applied by the manufacturer. All this assumes the land and groove diameters are matched to the projectiles you choose to shoot.
So called 5R rifling has a shallower angle on the land edges, with a fillet in the inside corners between land and the groove diameter. That is about as far as I would go "to reduce gas leakage and fouling". Certainly. proper 5R rifling has a reputation for long range accuracy; but even that depends on who made the barrel.
Poly rifling this far from spline rifling is more likely to skid and crush projectiles:
Compare the above to 5R rifling
And conventional rifling:
From: https://vortakt.com/selecting-different-rifling-styles/
Also see poly rifling study: https://journals.sagepub.com/doi/pdf/10.1177/00368504211016954
For pellet shooting, you could argue that RWS style wide but conventional looking lands, with narrow rounded or V-shaped grooves offer better "bore riding" pellet head support. Certainly better than the rounded lands of the "poly" barrel photo shown higher up in this thread. How either of them shoots matters more than what they look like. That depend heavily on how well the barrels were made, and how compatible the barrels are with the pellets being shot from them.
As for the title of this thread about "cut rifling"; very few airguns use cut rifling because that is very expensive to manufacture. Today, most airgun barrels are button rifled. Some are hammer forged. FX has an externally embossing process to produce low cost barrels. So, I assume the OP meant to compare polygonal rifling to conventional rifling, rather than cut rifling.
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And IMO a combo perhaps being the best of the most positive attributes might be ....
Hammer forged
Done to a high quality & consistency
Very smooth surface finish within bore
3 grooves
Enter the TJ manufactured special .22 3G
Hugh Jorgen sourced ( AKA: Troy Hammer )
It sure does shoot well be it pellets or correct size slugs.
Made for .217" size. Some weights of NSA .2175 also do well.
Hammer forged
Done to a high quality & consistency
Very smooth surface finish within bore
3 grooves
Enter the TJ manufactured special .22 3G
Hugh Jorgen sourced ( AKA: Troy Hammer )
It sure does shoot well be it pellets or correct size slugs.
Made for .217" size. Some weights of NSA .2175 also do well.
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Here is the story I heard. There were only a handful of Benchmark .25 barrels made ( confirmed by Benchmark). I have one of these .25 Barrels and they do shoot very well at 50 yards but I have not shot it at further distances. I will be tuning this barrel on a HM1000X, hopefully it will perform at 75 and 100 yards.
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Well but my BM500X is .22 and it has a cut rifled barrel (confirmed by Martin).
But he refused to tell that who made this barrel.
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Today tested some knockout slugs and some H&N 21 grain slugs through the cut rifled barrel but couldn't achieve any reasonable accuracy.
Anyone shoots slugs with RAW cut barrels?
Anyone shoots slugs with RAW cut barrels?
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