dvcopen Posted February 8, 2006 Share Posted February 8, 2006 (edited) The question is, if you think a barrel can be worn out after only 70K rounds? It is a 5.5 Schuemann AET Barrel (.355) with 2 TJ holes and a 7 port comp. As of last night my load is 9.6 gr of vv 3N38 behind a MG 124 JHP with OAL of 1.245 with a pretty tight crimp. This gives me a power factor of 166.2. I have given my rounds to other open shooter that run the same comp and TJ holes and there power factor is around 7 to 10 points higher. Also they don't have a 2 foot flame coming out their TJ holes. I have had to increase my powder drop and have even changed powders trying to resolve this problem. I have also tried to Zero's and go up in bullet diameter to a .356 with now real change in power factor or decrease in flame. Frank Edited February 9, 2006 by dvcopen Link to comment Share on other sites More sharing options...
redmercury2 Posted February 8, 2006 Share Posted February 8, 2006 What is the accuracy of the barrel compared to new? Link to comment Share on other sites More sharing options...
XRe Posted February 8, 2006 Share Posted February 8, 2006 Certainly, 70K of Major loads in an open gun can wear a barrel out. Pull the barrel out, and look down the bore from the chamber end. What does the rifling look like for the first inch in front of the chamber?? Starting to look smoothbore, or otherwise eroded? Is this a Major 9 gun?? If not, why the short OAL? 9.6gr of 3N38 makes 170PF for me in my .38 SC gun w/ a .356 bullet (125 HAP) - and that's 1.250" OAL. Link to comment Share on other sites More sharing options...
shred Posted February 8, 2006 Share Posted February 8, 2006 I have two identical guns where one PFs 5-8 points higher than the other with the same ammo, and always has. The key is if the same loads in the same gun now PF lower than they used to, and the accuracy isn't there, then it might be new barrel time. Link to comment Share on other sites More sharing options...
dvcopen Posted February 8, 2006 Author Share Posted February 8, 2006 (edited) The accuracy is still there, and the rifling still looks good. This is a 38supercomp gun. The only thing that is going on is I have to us alot more powder (almost a a full grain in some cases). an example of this is when using 7625 I needed 7.3 last February, by October I was at 8.1 to make the same 170 pf. I also started blowing primers at this point (reason for the powder switch). Frank Edited February 8, 2006 by dvcopen Link to comment Share on other sites More sharing options...
Anthony Lombardo Posted February 8, 2006 Share Posted February 8, 2006 The accuracy is still there, and the rifling still looks good. This is a 38supercomp gun. The only thing that is going on is I have to us alot more powder (almost a a full grain in some cases). an example of this is when using 7625 I needed 7.3 last February, by October I was at 8.1 to make the same 170 pf. I also started blowing primers at this point (reason for the powder switch).Frank Your barrel should be shot out by now, but this may be a case of comp baffle erosion.. Link to comment Share on other sites More sharing options...
eric nielsen Posted February 8, 2006 Share Posted February 8, 2006 PM sent Link to comment Share on other sites More sharing options...
smokshwn Posted February 9, 2006 Share Posted February 9, 2006 FWIW, I was told by a couple of shooters who spent a lot of time in open during the 175pf days and they were saying that you would actually "wear out the chamber" before the rifling was wore out. I asked for an explanation and they both indicated that the high pressure eventually makes the chamber slightly larger therefore needing more powder to make the same pf. I was skeptical but theoretically it makes sense. Link to comment Share on other sites More sharing options...
fastshuter Posted February 25, 2006 Share Posted February 25, 2006 This has nothing to do with an open barrel but from past experience with the power factor drop using the same powder load you may want to take a really good look inside your barrel and see if there is a ring around the inside. You may have possibly had a squib pushed through your barrel or it may be cracked. Happened on my Para last year. Also if your noticing more fouling in the gun it is because gases are escaping through the crack in the barrel. It was cracked around one of the lugs on mine. Just a thought but might be worth checking into. I was new to this kind of failure and didn't notice it until I shot a match and was stopped by an RO, he said my gun was cycling in slow motion at the time. Changed out parts from a spare gun and finished the match and had the gun fixed soon afterwards. Link to comment Share on other sites More sharing options...
markm Posted February 25, 2006 Share Posted February 25, 2006 As Roy said, the only valid comparison is what your gun is doing. Could be a temp change, humidity when reloading, powder storage problems, lot differences, primers, ect... Accuracy is normally the determining factor if a new bbl is needed... BTW I load SC to 1.235 OAL. Mark Link to comment Share on other sites More sharing options...
dvcopen Posted February 26, 2006 Author Share Posted February 26, 2006 Well Dererk from Millennium has the gun now. He said the chamber was worn from it being reamed to deep and the head space was way off. thanks to all who replied! Link to comment Share on other sites More sharing options...
CenTX Posted March 8, 2006 Share Posted March 8, 2006 Is this a Major 9 gun?? If not, why the short OAL? 9.6gr of 3N38 makes 170PF for me in my .38 SC gun w/ a .356 bullet (125 HAP) - and that's 1.250" OAL. When I talked to Bevin he recommended 1.225 for 38 Super for the best results (1.235 for 38SC). I have been loading to 1.225 for about 18 months now without any problems. Link to comment Share on other sites More sharing options...
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