Rs Barrels Spread (Page 1)

DAVID TUBB — the RIFLE SHOOTER BARRELS SEGMENT wear in the barrel so my seating depths will, ning on using them in all my competition onal rifling method since, for the same rea- twist rate. I was one of the first contending again, be at a known and proven setting. As rifles for the 2003 season. Polygonal rifling sons mentioned earlier, the bore is allowing shooters (early 1990s) using .243 Winchester explained in the ammunition segment, on a has a different land and groove configuration that much less gas blowby. The question, and here is where I learned that lesson. We brand new chamber my bullets are seated far- which essentially eliminates any right-angle then, is not what you’re not getting with a were first using the (then) new Sierra® 107 ther into the case than what I want. After the edges that come into contact with the bullet. polygon, but what you’re and also some vld-style first 200-300 rounds they are then right The result is less stress and friction on the not losing. Burning less bullets from custom mak- where I want them. All through the year I bullet jacket. Polygonal rifling has less ten- of the same propellant to ers and trying to deter- have been running experiments and noting dency to foul, and since there are no square get the same thing is not mine what was necessary behaviors and zeros, and the majority of that corners for the gas to flow by, may produce a at all bad. I have noticed to stabilize them. Con- information, or at least the most reliable slight increase in muzzle velocities. If you an absence of the typical sensus and comparison information, has come from barrels that are push a bullet through a firearm bore you can dark fouling streaks in both seemed to indicate from 25 to 75 percent maturated. Using this see light streaks around the lodged bullet. the throat area common that 1-9 twist (“one turn system, I could effectively shoot the same These are far less distinct in a polygon barrel. with conventional rifling, in nine inches”) was ade- barrel more than once at Camp Perry. That, I Additionally, the interior of the barrel is work and believe this is also quate. And it was, until think, is a big advantage. hardened more during this rifling process; due to less gas blow by we got to Camp Perry. My this lends itself to providing longer accurate with the polygon. Barrel home is at about 2500 BARREL CHOICE barrel life. A limited test (a few 10 round life should increase for feet above sea level and I [rifling styles] groups) might not show much, if any, advan- most applications due to experience typical West- The only assurance anyone has of barrel tage on target to this rifling system, but the less concentration of hot ern summers, meaning it quality is purchasing from a known good bar- advantages are there over the long run. gases directed at the bar- Polygonal rifling looks like a stretched “M” gets hot and stays dry. rel maker. That’s going to be an individual Extended accuracy (from reduced fouling) is rel steel. with no sharp lines. There is no sharp trail- My 9 twist reverse taper- who makes custom barrels. There are a few a big asset to the High Power shooter. Shoot- Additionally, seeing ing or leading edge angles. In a conven- ed silhouette barrel shot who deserve recommendation, but the one I ing a polygon barrel against a conventionally the commonplace dark tionally rifled barrel, the leading and trail- like a house afire at the take my business to is Gary Schneider. I use rifled barrel after both have had 100+ rounds streaks on either side of a ing edges of the rifling never obturates or Silhouette Rifle nationals Schneiders in all my across the course, long worth of fouling in them, in other words, is land indicates to me that fully fits that groove so, consequently, in Pennsylvania at 2000 range, and rimfires. All Schneider barrels are likely to display a difference on target (it cer- the bullet is not bearing there is some gas blowby. How well a bul- feet, and also my 9 twist let conforms to the bore, and how little hand lapped stainless steel. I have won what tainly does with a bore scope). in that area either. Con- across the course barrel deformation or stress is on it has to make I have won, with three exceptions, using a My experience with these polygon bar- sidering their absence in shot well at the other a difference. Better fit contact and more Schneider barrel. The three exceptions were rels has been that they take less propellant to a polygon barrel, I also trips I made with that even bearing means there should be less using a Hart in my .308 for one early Camp attain the same velocities as a conventional have to believe that there combination to Okla- displacement of jacket material. Perry win, an Obermeyer for a Palma® win, barrel. Comparing new barrels, it’s approxi- is greater contact being homa City, which is and a factory Remington® barrel to win the mately 1-2 full grains of powder. That’s a made with the bullet in about the same profile as Silhouette Rifle nationals one year. Schnei- good deal of difference, and definitely some- this configuration. That also somewhat home, to Raton (6500 feet), and to Bailey, Col- der is the barrel used on each TUBB 2000. thing to be aware of before working up a load would explain the experience of polygon tak- orado (8000 feet). But at the 600 feet eleva- Again, there are a lot of good barrel makers in a new polygon barrel. Keep in mind that I ing less propellant, and points out a possibil- tion in Ohio, the 9 twist cost me a win that from which to choose but I have stayed with am speaking from a lot of experience in using ity that polygonal rifling might work that year. The rifle would not shoot up to my stan- the one that has been proven to me to work. conventionally-rifled Schneider barrels and much better with a moly coated bullet. dard. I remember one 300 rapid string of 100- I began experimenting with Schneider also am using the same chamber reamers, All TUBB 2000s have polygonal rifling 0x, and that said it all. polygon barrels in the early 1990s and was loading components, and conducting these and we have been setting records with them. Now, several years later, I’m back to impressed with them. I used them in .308 tests in a known control environment. I men- using 6mms and I’m using a 1-8 twist to drive and 7mm but couldn’t get Gary to build them tion those things because it otherwise is diffi- [twist rate] them. Using bullets suitable for High Power for smaller calibers (they are very difficult to cult to know how accurate other comparisons I have some hard-learned advice to share shooting, there will be no ill effects from lap) until late in 2002. Now that I have might be. I attribute the difference in powder on twist rate selection. If there is any ques- going one turn faster than you think you 6.5mm and 6mm polygon barrels, I’m plan- charges to the greater efficiency of the polyg- tion, and an option, go the next step faster in might need. The rifle shot as well the next 326 327.

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