n5qm Posted April 18, 2014 Share Posted April 18, 2014 (edited) All, I have 1k of the 135gr BBI that I am currently working with. I noticed some pretty significant variations in OAL and started checking each component individually and I am measuring a spread of up to 0.010" on the height of the bullets. Is this a normal variation for a coated round? I am assuming it is just the thickness of the coating that is varying between bullets? Robert Edited April 18, 2014 by n5qm Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted April 18, 2014 Share Posted April 18, 2014 I'm guessing you're using the bullets for 9mm minor? I wouldn't worry if the bullets were one - one hundredth of an inch shorter or longer ... What is a "significant variation in OAL"? Link to comment Share on other sites More sharing options...
Steve RA Posted April 18, 2014 Share Posted April 18, 2014 I gather you are speaking of the length of the bullets themselves and not a loaded cartridge. If the bullets, then it's sort of immaterial as any variation in length of the bullet will be inside the case when loaded. Won't have any affect on the cartridge OAL. Link to comment Share on other sites More sharing options...
n5qm Posted April 18, 2014 Author Share Posted April 18, 2014 (edited) I measured the length of the bullets themselves after noticing the variations on COAL, which has a spread of nearly 20 thousandths. Based on further reading I'm going to try lubing the cases to see if that helps. I'm loading on a XL650 and the shell plate is snug. Edited April 18, 2014 by n5qm Link to comment Share on other sites More sharing options...
SilverBolt Posted April 18, 2014 Share Posted April 18, 2014 Did you happen to weigh them? .02 variance I am betting will lead to a fair large difference in weight. A bullet set .02 deeper in the case will have an impact on pressure. Link to comment Share on other sites More sharing options...
cslafrain Posted April 18, 2014 Share Posted April 18, 2014 With a RN profile the length of the bullet is slightly affected by the sizing process as 1 bullet is used to push another bullet thru the sizing system. The seating die should use the give of the ogive of the bullet and not the tip. That way the bullet is seated to the same depth based on the base dimension inside the case. I used to see the same thing in my 550 with the standard Dillon dies. Changed to a redding competition seating die and problem solved. Call us if you have some question. Sent from my DROID RAZR using Tapatalk Link to comment Share on other sites More sharing options...
n5qm Posted April 18, 2014 Author Share Posted April 18, 2014 Ahh, that makes sense. Should I try the method I have stern mentioned where you use some hot glue in the seating die to improve the contact with the bullet? The Dillon die is leaving a little imprint right around the tip of the bullet. Link to comment Share on other sites More sharing options...
z40acp Posted April 18, 2014 Share Posted April 18, 2014 The bullet profile is probably the culprit but just as a precaution the next time you change calibers check the bolts that hold the base to the shaft. Link to comment Share on other sites More sharing options...
IDescribe Posted April 18, 2014 Share Posted April 18, 2014 I have experienced the same thing with the same bullet. There is a wider than average variance in the overall length of the bullet, as well as a wide variance in overall length of the cartridge if seating off the ogive, which I do with RN's. Also, if you are loading for pistols like CZ's that have shorter than average fee-bore, you're going to be loading those bullets DEEP into the case, right to the actual limit where the case walls start to thicken. It's less than ideal. It's the irregular thickness of the coating that causes the length variance. BBI is new to this coating, so hopefully it will get better with time. I liked BBI 125 and 147 with the old coating quite a bit. For the record, in testing with these bullets, I got excellent standard deviations, but accuracy sucked out loud. Link to comment Share on other sites More sharing options...
cslafrain Posted April 18, 2014 Share Posted April 18, 2014 I use that exact same bullet when I shoot SS minor and we have a BUNCH of CZ guys using them. This is the 1st I have heard of an accuracy concern. Off of a rest I shot 1-1/2 groups at 25 yds. Give me a call and we will see if we can work you issue out. I shot 15k of them since the coating change. Sent from my DROID RAZR using Tapatalk Link to comment Share on other sites More sharing options...
n5qm Posted April 18, 2014 Author Share Posted April 18, 2014 Chandler, I have been doing more reading and it looks like the Dillon seating die has a stem that is reversible, so I will "play" with that later tonight to see if it helps. I am new to all of this, so I am learning as I go.... Robert Link to comment Share on other sites More sharing options...
n5qm Posted April 18, 2014 Author Share Posted April 18, 2014 So, I took the seating die apart and out of the two sides of the stem, I think I am using the best choice. Disassembled die: The side of the stem I am using: The other side of the stem: Link to comment Share on other sites More sharing options...
n5qm Posted April 18, 2014 Author Share Posted April 18, 2014 I forgot to add that the bullet only makes contract with the stem at the very tip. Link to comment Share on other sites More sharing options...
bowenbuilt Posted April 19, 2014 Share Posted April 19, 2014 Also make sure to have all of your stations with a shell in place. Trying to do this with one shell at a time will cause all kinds of OAL problems. Link to comment Share on other sites More sharing options...
n5qm Posted April 20, 2014 Author Share Posted April 20, 2014 All, I made the modification to the seating stem using the hot glue method and was rewarded with a dramatic improvement. My COAL variations went from 0.020 to 0.005 in my sample groups. I documented what I did in the following thread. http://www.brianenos.com/forums/index.php?showtopic=194010 Thank you everyone for your help and suggestions! Robert Link to comment Share on other sites More sharing options...
cslafrain Posted April 20, 2014 Share Posted April 20, 2014 That's pretty awesome Robert. Thanks for posting. Sent from my DROID RAZR using Tapatalk Link to comment Share on other sites More sharing options...
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