Pat Miles Posted September 11, 2008 Share Posted September 11, 2008 Went out this morning to do some bullet and powder comparisons. Shot some MG 121 IFP's (7.9 gr IMR 7625, 1.240" OAL) and about half of them keyholed through the target. Also shot some MG 115 CMJ's (10.0 gr 3N38, 1.240" OAL) which did not tumble at all. Both loads were shot through my 38SC shorty at about fifteen yards. No indications of any bullets hitting the comp, either the 121's or the 115's. Both loads were loaded on my 650 with everything the same except for powder and amount of powder. Any of you other folks had problems with the 121 IFP's? CYa, Pat Link to comment Share on other sites More sharing options...
lynn jones Posted September 11, 2008 Share Posted September 11, 2008 check your bullet diameter and check the crimp on the bullets. lynn Link to comment Share on other sites More sharing options...
revchuck Posted September 11, 2008 Share Posted September 11, 2008 Pat - Shooting these at minor velocities in four different guns (SIG P6, two CZ-75Bs and a Beretta 92) resulted in nice round holes, fairly close together. Link to comment Share on other sites More sharing options...
Pat Miles Posted September 11, 2008 Author Share Posted September 11, 2008 Bullet diameters: 121's .3551" 115's .3554" Crimp is .003" Nothing was changed on the 650 (Lee sizer/crimp die, Redding Comp seating die, etc.) while loading either of these bullets. I'm going to shoot both through my 5" open gun tomorrow and see what happens. Both guns are Bedell's. CYa, Pat Link to comment Share on other sites More sharing options...
JThompson Posted September 11, 2008 Share Posted September 11, 2008 Went out this morning to do some bullet and powder comparisons. Shot some MG 121 IFP's (7.9 gr IMR 7625, 1.240" OAL) and about half of them keyholed through the target. Also shot some MG 115 CMJ's (10.0 gr 3N38, 1.240" OAL) which did not tumble at all. Both loads were shot through my 38SC shorty at about fifteen yards. No indications of any bullets hitting the comp, either the 121's or the 115's. Both loads were loaded on my 650 with everything the same except for powder and amount of powder. Any of you other folks had problems with the 121 IFP's? CYa, Pat I ran them in my STI with no issues, but that thing will shoot anything. I've heard of issues with Tanfo and Beretta though. Link to comment Share on other sites More sharing options...
scirocco38s Posted September 11, 2008 Share Posted September 11, 2008 Went out this morning to do some bullet and powder comparisons. Shot some MG 121 IFP's (7.9 gr IMR 7625, 1.240" OAL) and about half of them keyholed through the target. Also shot some MG 115 CMJ's (10.0 gr 3N38, 1.240" OAL) which did not tumble at all. Both loads were shot through my 38SC shorty at about fifteen yards. No indications of any bullets hitting the comp, either the 121's or the 115's. Both loads were loaded on my 650 with everything the same except for powder and amount of powder. Any of you other folks had problems with the 121 IFP's? CYa, Pat I have had 2 identical open guns and when shooting 124 montanas thru 1 it would occassionally keyhole where the other never did. I could find no evidence of comp being hit or baffle interference. Funny thing was if I removed the comp and shot it the tumbling stopped. The comp was the problem even though I could not prove it. I ended up changing the comp and the problem went away. I have since put that comp on another gun and it has not had the problem. I guess that there was just some kind of imbalance influencing the bullet as it went thru the comp and it was just enough to make it tumble. But for 2 identical guns to have diffeent results using the same components is very odd. The fact that the guns shoots 1 bullet with no trouble and then tumbles a different bullet isnt all that strange to me anymore. Link to comment Share on other sites More sharing options...
HSMITH Posted September 12, 2008 Share Posted September 12, 2008 .003" is WAY too much crimp, back that off and see what it does. Link to comment Share on other sites More sharing options...
dansy Posted September 12, 2008 Share Posted September 12, 2008 Shoot a few cases in 1 STI Barrel 9mm (STInger), 2 KKM (Beddel's Shorty)and 2 Barsto (Dawson's Shorty) barrels with out any key hole issued.....38 SC Link to comment Share on other sites More sharing options...
GentlemanJim Posted September 12, 2008 Share Posted September 12, 2008 I too have had a few 121s tumble in 38sc...in two guns both with kkm barrels Dont know why?? Jim Link to comment Share on other sites More sharing options...
Pat Miles Posted September 12, 2008 Author Share Posted September 12, 2008 Correction on the amount of crimp. Remeasured and found to be .0015". Just to make sure I know what I'm doing. Bullet diameter plus 2x cartridge wall thickness minus the measured diameter of loaded cartridge at the crimp equals the amount of crimp (rocket surgery!). CYa, Pat Link to comment Share on other sites More sharing options...
HSMITH Posted September 12, 2008 Share Posted September 12, 2008 A thou and a half is decent, if they aren't hitting the comp they should make nice round holes. That bullet is supposed to be a really accurate bullet too. Second thought, what twist barrels are these? The 121 is a stubby little bullet without a lot of bearing surface. Both of Jim's barrels are are 32 twist, the guy that put them in is kind of a dink but he does good work Link to comment Share on other sites More sharing options...
Matt Cheely Posted September 12, 2008 Share Posted September 12, 2008 I've had more than a few through the g/f's open 9mm. She knocks down plates on a plate rack at 100 yards with them... Link to comment Share on other sites More sharing options...
Pat Miles Posted September 12, 2008 Author Share Posted September 12, 2008 A thou and a half is decent, if they aren't hitting the comp they should make nice round holes. That bullet is supposed to be a really accurate bullet too.Second thought, what twist barrels are these? The 121 is a stubby little bullet without a lot of bearing surface. Both of Jim's barrels are are 32 twist, the guy that put them in is kind of a dink but he does good work Man, I haven't heard a person described as a "dink" in a loong time (lol)! Yeah, Jim and Nancy both said their smith was a dink but does damn fine work. The barrel is a KKM. Not sure of the twist rate. The 121 looks to have a longer bearing surface than the 115's. I bought a case of these because of their touted accuracy. I'll try some in my 5" gun (Schuemann barrel) tomorrow. Stay tuned boys and girls, Pat Link to comment Share on other sites More sharing options...
G-ManBart Posted September 12, 2008 Share Posted September 12, 2008 A thou and a half is decent, if they aren't hitting the comp they should make nice round holes. That bullet is supposed to be a really accurate bullet too.Second thought, what twist barrels are these? The 121 is a stubby little bullet without a lot of bearing surface. Both of Jim's barrels are are 32 twist, the guy that put them in is kind of a dink but he does good work Man, I haven't heard a person described as a "dink" in a loong time (lol)! Yeah, Jim and Nancy both said their smith was a dink but does damn fine work. The barrel is a KKM. Not sure of the twist rate. The 121 looks to have a longer bearing surface than the 115's. I bought a case of these because of their touted accuracy. I'll try some in my 5" gun (Schuemann barrel) tomorrow. Stay tuned boys and girls, Pat Pat, I'm putting a bunch of different conversations together so I may have something confused. My Bedell also has the KKM barrel that's the same as yours and Jim and Nanci's and I'm not getting any tumbling. I have one of the earlier Ti comps with the smaller opening in the last port and I had a couple of bullets tumble when they hit that, but after I opened up the last baffle a touch (in line with Dan's new specs), that stopped entirely. I recall talking to Nanci on the phone (she was measuring bullets while we were talking) when they were working up a load for the 121s and she thought their ammo was crimped a bit more than I was using (trying to diagnos a feeding issue) and that's around the time when I saw evidence of tumbling on Nanci's targets during a match. I'm going off memory, but I think I ran .378" at the casemouth. I'm not sure how much more bearing surface the 121 has over the 115 as I haven't measured it, but it seems pretty minor. It's the same basic bullet with the ogive moved forward just a touch to allow for the extra lead up front....really, just closing the hollow point area less than in the 115. Link to comment Share on other sites More sharing options...
Pat Miles Posted September 12, 2008 Author Share Posted September 12, 2008 I'm looking hard at the crimp. I found some muck muck in the Lee sizer/crimp die and cleaned it out. We will see. Bart dog, have you come to any conclusion regarding the comparison of 3N38 and N105? Last time we talked you were on the fence regarding the two. Thanks for all the input folks, Pat Link to comment Share on other sites More sharing options...
lcs Posted September 12, 2008 Share Posted September 12, 2008 Used thousands of MG 121 (9 Major) and no tumbling EXCEPT a T1 comp. For no apparent reason my bullets started tumbling. I took the gun to my smith and he opened the comp slightly and the problem was gone. Note: I run a pretty tight crimp to get Sil to burn real clean. I would think you'd have to really crank the crimp to cause tumbling on a MG bullet. Link to comment Share on other sites More sharing options...
Mick Posted September 13, 2008 Share Posted September 13, 2008 check your bullet diameter and check the crimp on the bullets.lynn Mike them...I have had constant issues with undersized MGs in several calibers. I rarely get a MG to measure near the .355" or .400", hence the tumbling... I went to Zeros and solved the problem. Link to comment Share on other sites More sharing options...
G-ManBart Posted September 13, 2008 Share Posted September 13, 2008 I'm looking hard at the crimp. I found some muck muck in the Lee sizer/crimp die and cleaned it out. We will see.Bart dog, have you come to any conclusion regarding the comparison of 3N38 and N105? Last time we talked you were on the fence regarding the two. Thanks for all the input folks, Pat Muck, muck....that's bad ju-ju for your ammo;-) On the N105, I'm happy with it, but I'll have to shoot more 3N38 for comparison before I really decide. If you want to give some of my N105 loads a try, I'll bring some extra to the next match and you can pop some caps afterwards. R, Link to comment Share on other sites More sharing options...
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