Crusher Posted February 24, 2006 Share Posted February 24, 2006 I don't know if this is a result of a "barrel cleaning" or a chrono error, so here is what transpired: First off I don’t clean my gun(s) as often as some, normally I wait to do a thorough cleaning until I notice some sluggishness in slide speed (I do wipe the rails and a few drops of oil every 600-800 rounds) but normally reserve detail cleaning and barrel cleanings to 3000-4000 round intervals. I recently used J-B Bore cleaners to remove copper fouling from the barrel (STI .40) on the last 2 cleanings about 2 months apart. I had chronoed some loads (over a CED Millennium under outdoor lighting conditions) during the time before using J-B and after the first cleaning with J-B and noticed a slight increase in FPS out of the barrel (10-15 FPS increase) using the same loads (powder type/charge, bullet type/weight, case head stamp, primer). After the last cleaning with J-B I noticed an increase of 60 FPS with the same load I always use (the power was from the same container for all chrono sessions with weights checked). I also checked the chono with another gun and loads and that combo registered to its normal velocity. The method I used with the J-B was to smear some cleaner on a bore snake and attach the snake to a fixed base and slide the barrel back and forth on the snake to remove all of the copper fouling that remained after patching the barrel clean, The barrel was warm (friction) after cleaning and the inside was mirror like shine. Accuracy was not affected whatsoever (25yd 1 1/2" groups freestyle both before and after) Is it likely that I made the barrel faster by polishing/cleaning with the J-B? I know J-B is very mildly abrasive cleaner but had no idea that it may be possible to increase a barrels speed. This is the only gun barrel I have used J-B on and I may run a few more chrono tests before trying this on another barrel of known speed with a specific load. Link to comment Share on other sites More sharing options...
Flexmoney Posted February 24, 2006 Share Posted February 24, 2006 Beats me. Sounds pretty neat. If you test some more, let us know. Link to comment Share on other sites More sharing options...
vluc Posted February 24, 2006 Share Posted February 24, 2006 Isn't that what the extrude process does? Forces a compound of some such through the barrel at high pressure to polish /improve. There was a thread on it around here somehwere.... Link to comment Share on other sites More sharing options...
TCK Posted February 24, 2006 Share Posted February 24, 2006 Accuracy buffs with rifes, fire several bullets with different grits of lapping compound to "fire lap" the barrel. This is to remove the microscopic burs and such that are formed during the rifling process. Link to comment Share on other sites More sharing options...
benny hill Posted February 24, 2006 Share Posted February 24, 2006 Accuracy nuts don't fire lap their barrels. We nuts get a preminum barrel from a great maker, hart,etc. You only use the fire lapping if you get a rough barrel. This does't happen to the benchrest crowd when you get one diamond dust lead lapped from the maker. Link to comment Share on other sites More sharing options...
blackdragon Posted February 25, 2006 Share Posted February 25, 2006 Did you change the recoil spring recently? Ivan Link to comment Share on other sites More sharing options...
Crusher Posted February 25, 2006 Author Share Posted February 25, 2006 (edited) Did you change the recoil spring recently? No, there were NO changes to the gun, load chrono used or the temp from last time I had chronoed the same batch of ammo. Another gun and ammo was used to check the chrono because I had some doubt as to the accuracy (60 FPS w/180 gr bullet is an increase in PF of over 10) This was the second time I had used J-B as a final copper residue remover and I had fired 300+ rounds through the gun before I tested the ammo. This is why I am wondering if I polished the bore with the J-B and possibly smoothed it up making it a little faster. Edited February 25, 2006 by Crusher Link to comment Share on other sites More sharing options...
blackdragon Posted February 25, 2006 Share Posted February 25, 2006 What powder? Ivan Link to comment Share on other sites More sharing options...
Crusher Posted February 25, 2006 Author Share Posted February 25, 2006 What powder?VV 320 Here is the deal: It's an STI eagle (factory) set up with a 10# recoil spring (minor PF only for IDPA/Steel) no changes made to the gun. Shooting a 180 Gr Percision Delta FMJ over 4.1 VV 320 at an OAL of 1.185" (OAL +/- 0002") all Rem once fired cases sized w/ a EGW Lee U die, with win primers (same case lot) loaded on a 1050. Before second cleaning w JB velocity was 735-750 FPS (after first shot 720 FPS, to warm thing up. I don't know why but it does that) After second cleaning 790- 810 FPS (after the first shot to warm things up, however the first shot over the chrono came out at 780) Over the next few weeks or so I'm going to test another gun (I have to clean it and I hate cleaning guns) and will set up a somewhat controlled test. I will use an STI Edge for this one the same chrono and a known sample of consistant ammo. Because now my curiosty is peeked. I wonder if it is possible to make your barrel shoot faster. Link to comment Share on other sites More sharing options...
blackdragon Posted February 25, 2006 Share Posted February 25, 2006 In the old days it was!!! Heavier recoil spring, Lots of Break Free! Ivan Link to comment Share on other sites More sharing options...
kevin c Posted February 25, 2006 Share Posted February 25, 2006 How old is the barrel? If it's new, could it have been a bit rough? Just speculating. Kevin Link to comment Share on other sites More sharing options...
Crusher Posted February 25, 2006 Author Share Posted February 25, 2006 How old is the barrel? The barrel is an STI with roughly 20k through it. Link to comment Share on other sites More sharing options...
DaG Posted February 25, 2006 Share Posted February 25, 2006 Was there a difference in temp. between the 2 chrono sessions? DaG Link to comment Share on other sites More sharing options...
Crusher Posted February 25, 2006 Author Share Posted February 25, 2006 Was there a difference in temp. between the 2 chrono sessions? Not really, maybe 8-10 degrees. Today I'm going to clean another gun, (no J-B bore cleaner) just a good scrubbing with solvent, patches and a brush, early next week I will chrono some known (chrono test ammo, Win white box) and use that as a baseline for the barrel. Then I will scrub the barrel and apply some J-B to the bore snake and clean the barrel, re-test same ammo (record) and clean one more time with the J-B for final results. I can say that the "shine" (with a bore light) from the first barrel appears to be much brighter than when the barrel was new. Link to comment Share on other sites More sharing options...
Crusher Posted March 5, 2006 Author Share Posted March 5, 2006 Ok established a baseline test. STI Edge factory barrel (20k round roughly on the gun) clean barrel (no JB yet) Winchester 165 gr (wally world value pak, same lot ammo) outside air temp 39 deg F Time of day 13:00 partly cloudy CED Millenium chrono No chrono error readings for 5 shots string Vel 1042 1031 1016 1056 1057 Avg Vel 1040.4 PF 171.66 End of baseline I just fnished cleaning barrel, Shooters choice patches and a brass brush then ran barrel on fixed bore snake (loop end of bore snake attached to loading bench) impregnated with JB Bore cleaner, patched barrel with solvent then ran dry patches until patches came out clean (no black residue). Next, chrono test and will post (probably Tues/Wed same time of day and temps look to be within 3-4 deg according to advanced weather reports) Link to comment Share on other sites More sharing options...
Gregory_k Posted March 7, 2006 Share Posted March 7, 2006 use JB to much and you will ruin your barrel. Link to comment Share on other sites More sharing options...
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