PaulW Posted November 26, 2003 Share Posted November 26, 2003 Many years ago when the power factor, for all practical purposes, was about 185,000 the pressures were so high that 0.355 bullets would upset and fill the barrel bore. When the power factor was decreased this no longer happens. Before the old days of 38 Super major everyone understood that a jacketed bullet had to be 0.001 to 0.002 inch larger than the groove diameter. That law hasn't been repealed. So, you have been shooting bullets that, at the present power factor, are too small. This has allowed gas to flow past the bullet, more so near the chamber where the pressure is highest. This produces gas cutting which accelerates bore wear. Going to a lighter bullet will aggravate the problem as the pressure will be even higher. The solution is to shoot a minimum of 0.356 and preferably 0.357 jacketed bullets. I use bulk 0.357 jacketed revolver bullets, usually Remingtons, though I have no reason to think Winchesters would be inferior to the Remingtons. I just like the Remingtons because the bullet nose is a little less pointed, which helps feeding. The basic problem is that when the bullet enters the bore the lands squeeze inward on the bullet. This shrinks the bullet diameter and makes the bullet longer. So, your 0.355 bullet becomes about 0.354 or 0.353 as it enters the bore, depending on where between the lands you measure the diameter. When you shoot a 0.357 bullet, it is shrunk to about 0.355 when it is going down the bore, and therefore can seal the gap between the bullet and the bore. Wil Schuemann Link to comment Share on other sites More sharing options...
tightloop Posted November 26, 2003 Share Posted November 26, 2003 Paul The point of all that is...? Link to comment Share on other sites More sharing options...
TDean Posted November 26, 2003 Share Posted November 26, 2003 Interesting. I wonder if there really is more measurable wear using smaller diameter bullets that don't "upset" to fill the bore. Back to the days of 185PF: Why would shooters choose to shoot a smaller diameter bullet at 185PF and hope that it fills the bore rather than .356-7 bullets that don't need to swell to seal the barrel? What's the original advantage there? Wouldn't it be best if 185PF shooters and 165PF shooters all used .356-7" dia bullets? Link to comment Share on other sites More sharing options...
PaulW Posted November 26, 2003 Author Share Posted November 26, 2003 Tightloop, The point of it all is just discussion. Curious if any one ever compared groups using .355, .356, and .357 bullets. The post started when a friend of mine emailed Wil regarding the accuracy he was getting from his short super. When he first got the gun it grouped better than what he is seeing now after 5k rounds through gun. So he emailed WIl and that was his response. Link to comment Share on other sites More sharing options...
Chriss Grube Posted November 26, 2003 Share Posted November 26, 2003 The higher pressures needed to make a 175 PF over the 165 Obtuated(sp) the bullet and sealed the bore. It is the same reason lead bullets need less powder to make the same PF compared to Jacketed. When I switched to 9major I tried the .355 bullets and the velocity was all over the place switched to .356 bullets with everything else being the same and they chronoed like clockwork. Link to comment Share on other sites More sharing options...
tightloop Posted November 26, 2003 Share Posted November 26, 2003 Paul Thanks, now I get it.. Link to comment Share on other sites More sharing options...
L9X25 Posted November 27, 2003 Share Posted November 27, 2003 To add one more facet to the hypothesis ... When we were shooting 180pf, with early "light bullet" supers, we were usually already on the "ragged edge" of pressure problems with the .355 bullets. When we increased the diameter to .356 or .357 (in a .355 bore) we increased the peak pressures to the point that they became critical. Shooting the .355 bullets kept the pressures low enough to allow us to make major within the pressure capacity of the components. I cannot tell you if the pressure reduction came from leakage around the bullet or just reduced energy necessary to initially push the bullet through the bore but it was significant at those pressures. Paul, To answer your question about accuracy... if the barrel is already fully stabilizing the bullet, you will see very little improvement in accuracy, if any. If your barrel is worn to the point where your bullets are not being completely stabilized you can notice a significant improvement in accuracy. If you take the "bigger bullet" theory too far you can actually degrade accuracy by deforming the bullet excessively, as it enters the bore, and making it inconsistent. Leo Link to comment Share on other sites More sharing options...
shred Posted November 27, 2003 Share Posted November 27, 2003 Hmm... I run an "old" 175 PF load in my short super to get the PF up to 165. It's still plenty accurate after 20K rounds of .3555 bullets, so I'll probably keep using them. Link to comment Share on other sites More sharing options...
eric nielsen Posted November 27, 2003 Share Posted November 27, 2003 I prescribe three grains of salt. Link to comment Share on other sites More sharing options...
TheOtherErik Posted November 27, 2003 Share Posted November 27, 2003 I've compaired the .355 and .356 and noticed no measureable difference in accuracy. No real difference over the chronograph. I run a 115g .355 at near 180PF in my open gun no problem. ....This produces gas cutting which accelerates bore wear. Going to a lighter bullet will aggravate the problem as the pressure will be even higher. If this is true and I were Will, I surely wouldent publish this information. Just think of all the barrels he could be replacing..... Link to comment Share on other sites More sharing options...
gm iprod Posted November 28, 2003 Share Posted November 28, 2003 Use .355" diameter barrels and projectiles and all this disappears. I have shot 40,000+ (admitedly Minor PF for NRA AP) rounds through my Lisner 9mm barrel chambered for 38Super with a match reamer. So I should according to the first post have a stuffed barrel, or at the very least a barrel that will be very soon nearly useless. I get consistant 140pf and 2" groups at 50y. A freind of mine who has the same brand barrel has just had to replace his after only shooting 200,000 rounds all jacketed through his barrel. This smooth bore (and it has very little rifling) still holds 4-5" at 50y when shot with minor PF 115gr Zero or Montana Gold. It will also still stay around the 4-5" when shot with major PF. As far as the accuracy drop off. I would reccomend he has his barrel / slide / frame fit checked regularly. My NRA AP gun needs to be looked at every 20,000 rounds to maintain optimum accuracy. But I found that by being more careful in my reloading practices and make your loads as good asthey can be you can leave the frame for 50,000 rounds as I can't shoot good enough, in a match, to be certain that it is the pistol. My IPSC open gun shoots 9mm 125gr Zero's into about 3" at 50 and easily makes 165PF without any fuss. Use the right bullets for the barrel and the right powder and have at it. It will also shoot the .356" 38Super 121gr about the same and also makes major no problems. Link to comment Share on other sites More sharing options...
Ross Carter Posted November 28, 2003 Share Posted November 28, 2003 IIRC the original spec for 38 super was .356 bore diameter. In modern times all the barrels I see are generic .355 bore and can be chambered for 9xwhatever or 38 super. I don't see .355 bullets being a problem in modern barrels, I've used lots of them in accuracy applications with outstanding results. Link to comment Share on other sites More sharing options...
10ring Posted November 28, 2003 Share Posted November 28, 2003 TheOtherEric - I suspect Wil came up with that "story" so he wouldn't have to replace barrels. Link to comment Share on other sites More sharing options...
Liota Posted November 28, 2003 Share Posted November 28, 2003 TheOtherEric - I suspect Wil came up with that "story" so he wouldn't have to replace barrels. You may be onto something there. Link to comment Share on other sites More sharing options...
TheOtherErik Posted November 28, 2003 Share Posted November 28, 2003 Im no balistics expert, or engineer of anysort, but I do think that most of his stuff is therory and speculation. People have been cleening their barrels since the black powder days.... If we weren't suposed to, some one would have found out that cleaning causes barrel degradation along time ago. People using .38 supers have been using .355 dia bullets for who knows how long with no adverse effects. My barrel has .355 stamped on the hood and by golly thats what I'm gonna put in it. Blah! Link to comment Share on other sites More sharing options...
George Posted November 28, 2003 Share Posted November 28, 2003 I've always been of the opinion that a bullet .001"-.002" larger than bore size is advantageous to provide complete obturation of the barrel and full usage of the peak pressure spike to propel the projectile, rather than gas cutting a new barrel throat for the first few micro-seconds of the process. Note that jacketed rifle bullets are universally .001" oversize for caliber, this says something to me. I think .001" oversize for bore is perfect for high pressure pistol loading. I like to slug a pistol bbl to see what the heck it actually is before I start high pressure loading for it. I shoot custom sized (.357") 147gr hard cast lead bullets in my .38 super with no noticeable leading because that bbl is actually .356". I had previously tried .356" lead bullets and got large amounts of leading just past the chamber due to gas cutting when the projectile didn't immediately seal the bore, so I had a local supplier size em larger for me (.357) and the leading went away. Whenever I shoot jacketed in that gun, I use .38 projectiles that are sized to .357" because that is what gives best results. It will definitely increase barrel life if the projectile fully obturates, instantly. In my niners, I strictly use .356" lead & jacketed because (almost) all 9mm bbl's have .355" bores. Wil may be a "mad" scientist, but he is a "scientist" nonetheless. Regards, Link to comment Share on other sites More sharing options...
Jager1147 Posted December 1, 2003 Share Posted December 1, 2003 I shoot 9x21, and the .355 bullets will not group, but the .356 group beautifully. I'm using a Storm Lake 9mm barrel in a TZ-75 Link to comment Share on other sites More sharing options...
Flexmoney Posted December 1, 2003 Share Posted December 1, 2003 Wil may be a "mad" scientist, but he is a "scientist" nonetheless. We talked on this a little bit while driving to a match this weekend. It seems that Wil stamps his barrels .355 ? I would have thought that the .355 stamp would have been the caliber to use in a .355 stamped barrel. Perhaps Wil is simply stating that the barrel is cut to .355??? Link to comment Share on other sites More sharing options...
Steve Anderson Posted December 1, 2003 Share Posted December 1, 2003 Makes me insane, as I told Flex on the drive. Last time I checked .356 vs. .355 I didn't see much difference in accuracy. George, are you George from egw? I'm on the list for a Caspian rebarrel and want to get the bullets right with the new barrel. I guess I'll switch to .356 when my .355s run out. I'll be .356 in the new barrel and just leave it. Would this gas coming around the smaller bullets affect the way the comp works/feels? Steve Link to comment Share on other sites More sharing options...
George Posted December 1, 2003 Share Posted December 1, 2003 I would have thought that the .355 stamp would have been the caliber to use in a .355 stamped barrel. Perhaps Wil is simply stating that the barrel is cut to .355??? Typically (but not always as is the way of the world) the .35whatever stamped on any bbl means the diameter groove to groove (max dimension). This means that a .355 bbl will be filled completely with a .355 projectile with the lands actually biting into the bullet a little. George, are you George from egw? Nah!, not me. I am actually a Geoff. I just got pegged with the nickname "George" because the folks at a large match a long time ago made an assumption that anything starting with Geo... had to be George, and the moniker stuck among my shooting peers. So it is now my competition Nom de Guerre. ould this gas coming around the smaller bullets affect the way the comp works/feels Probably not, but the pressure increase from the larger diameter projectile will definitely affect things at the comp by providing a higher pressure there. Regards, Link to comment Share on other sites More sharing options...
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