seabee23 Posted March 8, 2011 Share Posted March 8, 2011 Hello all. I try to do more reading on here than posting, but I need some help. I worked up some 9mm to test this past weekend and didn't get the results I was looking for. My loads were win brass with MG 115 bullets. They consisted of powder from 4.0-5.0 of Win 231. My velocities were good, and I took my time to keep the barrel cool. The problem was with accuracy. At 7yds, I can shoot about a quarter size group with factory loads but when I shot my reloads, it opened up to about six inches with all powder loads. Any idea what the issue may be? By the way I shoot a storm lake barrel out of a G31 and I also use a Lee U die and crimp. Any possibility my crimp is too tight? Link to comment Share on other sites More sharing options...
GrumpyOne Posted March 8, 2011 Share Posted March 8, 2011 Every possibility that the crimp is too tight....Were they keyholing? The crimp should just remove the bell/flair put into the case at the powder drop station. Link to comment Share on other sites More sharing options...
seabee23 Posted March 8, 2011 Author Share Posted March 8, 2011 No keyhole, just a very large group. Link to comment Share on other sites More sharing options...
GrumpyOne Posted March 8, 2011 Share Posted March 8, 2011 Sounds like you've over crimped them... Link to comment Share on other sites More sharing options...
seabee23 Posted March 8, 2011 Author Share Posted March 8, 2011 Ok thank you. I will give that a shot and see what happens. Link to comment Share on other sites More sharing options...
RH45 Posted March 8, 2011 Share Posted March 8, 2011 MG bullets have a pretty tough jacket. If you were loading a plated bullet, and overcrimp, I could see that being a problem. I only crimp enough to remove all the "bell" for autoloaders. You might want to try varying your overall length, or, try a different brand/weight of bullet. Every once in a while, you'll run across a barrel that just hates a particular bullet. What kind of pistol are you trying to run them through? Link to comment Share on other sites More sharing options...
seabee23 Posted March 8, 2011 Author Share Posted March 8, 2011 It is a G31 with a storm lake barrel. My OAL is 1.137. The factor Winchester white box is 1.158. The Winchesters are tack drivers out of that barrel. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted March 9, 2011 Share Posted March 9, 2011 At 7yds, I can shoot about a quarter size group with factory loads but when I shot my reloads, it opened up to about six inches with all powder loads. Wow, I didn't think there was ANYTHING you (or I) could do to get groups that large (6" at 7 yds is like 20" at 25 yds)??? How is the noise, recoil? Does it feel anything like a factory load? Are you sure you're using .355" bullets? Are you positive your OAL is 1.13"? Is the group round, or vertical, or horizontal? Sorry, I guess this isn't too helpful, but I can't imagine any factor which would cause such a large degree of inaccuracy. Can't wait to find out what the problem actually was. Jack Link to comment Share on other sites More sharing options...
CocoBolo Posted March 9, 2011 Share Posted March 9, 2011 I don't want to start a riot so read carefully. My open guns (9 major) which have Clark Barrels which are rumored to be Storm Lake barrels do not shoot 115gr bullets well. By that I mean a 1 1/2" groups at 25 yards w/125gr versus an 8" group with 115gr Zero or MTG RN bullets. The only variable other than the bullet being +100 fps aka 1501 fps avg. It is possible that your barrel/gun will not shoot these bullets accurately, try some 125gr, or another brand of 115gr like Zero. Response based upon - assumption - that crimp was determined to not be the cause of the issue. Link to comment Share on other sites More sharing options...
seabee23 Posted March 9, 2011 Author Share Posted March 9, 2011 Jack, the bullets are .355 MG. I double checked AOL and yes that measurement is correct. I have some spreer and siera bullets to try. I loaded up another batch to hopefully try this weekend. I backed off the crimp and made the AOL 1.16 to try. Thanks everyone for the info and keep the suggestions coming. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted March 9, 2011 Share Posted March 9, 2011 Jack, the bullets are .355 MG. I double checked AOL and yes that measurement is correct. I have some spreer and siera bullets to try. I loaded up another batch to hopefully try this weekend. I backed off the crimp and made the AOL 1.16 to try. Thanks everyone for the info and keep the suggestions coming. What shape are the groups? Round? Vertical? Horizontal? Good luck - hope the 1.16" fit in your mag/chamber? Jack Link to comment Share on other sites More sharing options...
seabee23 Posted March 10, 2011 Author Share Posted March 10, 2011 The group was round. The 1.16 fits but barely. Do you have a recommended length to try out? Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted March 10, 2011 Share Posted March 10, 2011 The group was round. The 1.16 fits but barely. Do you have a recommended length to try out? If the cartridges fit, that's all that matters - actual best OAL is very personal to you, your gun and your ammo. I can't imagine that lengthening the OAL from 1.13 to 1.16 will solve your particular problem (huge group size) but won't hurt any. I can't wait to find out what would cause such large sized groups?? If you have access to a bullet puller - why not pull one round and see if you've crimped the bullet so hard that there's a deep indentation on the bullet? Shouldn't be too much of a line there. I've never heard of such large groups out of an otherwise accurate gun??? Good luck with it. Jack Link to comment Share on other sites More sharing options...
gng4life Posted March 10, 2011 Share Posted March 10, 2011 What is crimp measurement?? With a 9mm, it should be about .375 or so, depending on the brass but that's a good estimate. Most of mine come out at .374-.377, depending. Also, I agree with CocoBolo about the bullet/barrel combination - I've seen that before but not to that degree of group size. Let us know... Link to comment Share on other sites More sharing options...
seabee23 Posted March 10, 2011 Author Share Posted March 10, 2011 Crimp is .375. I pulled one the other night, and not so much as a scratch on the bullet. Link to comment Share on other sites More sharing options...
lcs Posted March 10, 2011 Share Posted March 10, 2011 The group was round. The 1.16 fits but barely. Do you have a recommended length to try out? Glock mags contribute more to max OAL. 1.150 should be good. 1.150 allows for +or - variation of all OAL factors while reloading. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted March 10, 2011 Share Posted March 10, 2011 Crimp is .375. I pulled one the other night, and not so much as a scratch on the bullet. I believe that means you're not overcrimping??? I May be Wrong??? For the life of me, I can't imagine such a wild dispersion !! When you figure out what the problem is, PLEASE let us know - I'm dying to find out. Sorry I can't be of any more help - wish I could. Jack Link to comment Share on other sites More sharing options...
seabee23 Posted March 10, 2011 Author Share Posted March 10, 2011 Thanks everyone for the suggestions. I have drill this weekend, so no testing. Hopefully next weekend. I will let everyone know the verdict. Link to comment Share on other sites More sharing options...
seabee23 Posted March 11, 2011 Author Share Posted March 11, 2011 Ok, so those of you that are as confused as I am about what's going on, it gets worse. I came home today and figured I would play around with some crimps. Correct me if I'm wrong, but the crimp is to avoid setback, correct? Well I made up a few dummy rounds. The first thing I decided to try was no crimp. This gave me a measurement of .378. No where near .375. I tried putting some thumb pressure on the round to see what kind of pressure it would take to get setback. Pushed hard, and harder yet till my thumb hurt. Nothing, no setback. I am using a Lee U die. Is this possible to get literally no setback with no crimp? I did the same pressure on all six dummies, case gauged them and chamber checked them. All good. Now I am so confused. By the way I rechecked a few rounds I had left from the weekend and they were not over crimped. They had a measurement of .376. Sorry to be a pain in the butt, but I'm off the confusion cliff. Would it make any difference that they are cmj instead of fmj if I'm not pushing really hot loads? Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted March 11, 2011 Share Posted March 11, 2011 Correct me if I'm wrong, but the crimp is to avoid setback, correct? Is this possible to get literally no setback with no crimp? By the way I rechecked a few rounds I had left from the weekend and they were not over crimped. They had a measurement of .376. I'm on the wall with you - can't figure this out. No, crimp is to assure feeding - not avoid setback. Sounds like you're definitely not overcrimping ... Undercrimping will mean you'll have rounds not chamber properly. Have you checked velocity of your rounds? Fired any groups, lately, with factory ammo (still getting small tight groups?) Is it possible your sights have shot loose - happened to me with a Colt Gold Cup and an STI TruBor - Still thinking ... Jack Link to comment Share on other sites More sharing options...
seabee23 Posted March 11, 2011 Author Share Posted March 11, 2011 Haven't had time to test anything yet, but its definitely not the sights because I shot factory ammo at the end of the day. I don't know if this means anything, but I notices on all the bullets of the dummy rounds that I chambered in the gun have some small lines on them almost like they are hitting the very edge of the rifling. It is only about an eighth of the way around the bullet. Link to comment Share on other sites More sharing options...
ChrisW Posted March 11, 2011 Share Posted March 11, 2011 Lines are usually from the rifling. You may also need to push the bullet in a little to get it to fully chamber and this means they are a little too long. Shorten you OAL a little at a time until the bullet will drop all the way into the chamber and drop out as well. If it gets stuck and needs pulled out it is still probably too long. You can try several different OAL's and see which is more accurate and then stick with that OAL. Make up about 20 of each and write on a baggie what the OAL is and then as you shoot them see which are most accurate. Chris Link to comment Share on other sites More sharing options...
gng4life Posted March 11, 2011 Share Posted March 11, 2011 Haven't had time to test anything yet, but its definitely not the sights because I shot factory ammo at the end of the day. I don't know if this means anything, but I notices on all the bullets of the dummy rounds that I chambered in the gun have some small lines on them almost like they are hitting the very edge of the rifling. It is only about an eighth of the way around the bullet. Did the factory ammo also have the same marks? Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted March 12, 2011 Share Posted March 12, 2011 its definitely not the sights because I shot factory ammo at the end of the day. I don't know if this means anything, but I notices on all the bullets of the dummy rounds that I chambered in the gun have some small lines on them almost like they are hitting the very edge of the rifling. Were the factory ammo groups around 1"? I'd definitely shorten your OAL - check accuracy at 1.12" OAL. Jack Link to comment Share on other sites More sharing options...
tunakilla Posted March 15, 2011 Share Posted March 15, 2011 Try another bullet, I have had similar observations with the MG 115 fmj and MG 115 cmj that CocoBolo has had. For some reason these don't work in a few of MY guns, different barrels. I love everything else that Montana makes. The 115 jhp is totally different story and seems to group well in all guns I have tested for accuracy. The MG 124 jhp is my favorite for Open and the 121 ifp tests look very promising for the World Shoot since we cant bring HP ammo to Greece? Link to comment Share on other sites More sharing options...
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