smokshwn Posted November 1, 2004 Share Posted November 1, 2004 I am setting up my 650 to load 9mm major for my new open gun. My gunsmith gave me a load for the gun but I forgot to ask about how much crimp he was running. By the dimensions I get .013 + .013 + .355 + .381 or call it .380 for an even number. I have measured several different factory rds I have handy and they all run .375. So as I was setting up for 125gr zero jhp's at OAL of 1.170 and with the crimp at .375 I was able to push the loaded round against the table and get movement. I increase the crimp to .370 and although it was a little better I still got .008 of movement with strong thumb pressure. So the question is, more crimp? or do I have enough crimp and I'm just putting to much pressure on the bullet in my little subjective test (pushing the round against the table)? I realize loading the 9 long doesn't leave much bullet in the case but at the same time I would rather not risk too much setback and cause a kaboom. Thanx in advance, Craig Link to comment Share on other sites More sharing options...
TRG65 Posted November 1, 2004 Share Posted November 1, 2004 You might need to check your sizing die sounds as thought your case body isn't getting compressed enough. I use a crimp of .377-.378 with a Zero 147 JHP loaded to 1.155. I don't get any setback on the thumb test. There shouldn't be a need for much crimp other than to get rid of the flare. I use a set of Redding dies in my 1050. Link to comment Share on other sites More sharing options...
Tri Burst Posted November 1, 2004 Share Posted November 1, 2004 I believe in the Lyman reloading manual it give the proper size of the case mouth after a crimp has been applied. I'm not near my manual but will look it up when I get home. Link to comment Share on other sites More sharing options...
DougCarden Posted November 1, 2004 Share Posted November 1, 2004 I will assume that you are using one type of brass only. Resize one case, then measure the case mouth. Then prime and flare the case, dump the powder, then run it through the crimp die until you get the measurement that you originally got from the resized case. This will give you an approx. crimp to shoot for, but you might need more or less. I too am concerned about your sizing die if you can still push in the bullet, unless you are belling the case way too much. Good luck and hope this helps. DougC Link to comment Share on other sites More sharing options...
smokshwn Posted November 1, 2004 Author Share Posted November 1, 2004 OK, I hadn't thought about the sizing Die. I have a brand new set of Dillon dies for 9. I will check that, thanx, Doug. case mouth after sizing die .375 bell to approx. .390 (dillon manual says .020it seems .015 is plenty) 12gr zero .355 set to OAL 1.170 final crimp .375 I will set some with a crimp of .370. Does anyone think this is TOO much crimp? Link to comment Share on other sites More sharing options...
robomanusa Posted November 1, 2004 Share Posted November 1, 2004 try backing off a bit, you might be applying too much crimp and swelling the case outwards. Link to comment Share on other sites More sharing options...
J.L. Hardy Posted November 1, 2004 Share Posted November 1, 2004 craig, i have found that the dillon resizing die won't bring the case down tight enough to hold the bullet firmly. at least 3 of us here in georgia have had the same problem and changed the resizing die to hornandy's and problem fixxed. the problem was worse on some headstamps of brass. good shooting, j.l. hardy Link to comment Share on other sites More sharing options...
smokshwn Posted November 1, 2004 Author Share Posted November 1, 2004 J.L. what final size is your brass after resizing. I hope I don't need a new die, I actually talked to quite a few people who were very happy with their dillon 9 dies. Dammit Robo, Do you mean backoff farther than the original .375 or backoff the .370? Thanx you guys I will get this figured out yet. Link to comment Share on other sites More sharing options...
robomanusa Posted November 2, 2004 Share Posted November 2, 2004 Yes I mean back off to around .377-.379 and see what happens. Awhile back I was putting way too much crimp on some of my loaded rounds and was swelling the case walls out a bit. which let the bullet rock back and forth...maybe this is what you have done???? Link to comment Share on other sites More sharing options...
smokshwn Posted November 2, 2004 Author Share Posted November 2, 2004 copy that I'll try a couple and see what happens Link to comment Share on other sites More sharing options...
RePete Posted November 2, 2004 Share Posted November 2, 2004 I had crimp problems last year, so what I did was take a factory round and measure the case mouth and set the die to that measurement. No more problems. RePete. Link to comment Share on other sites More sharing options...
MikeyG23 Posted November 2, 2004 Share Posted November 2, 2004 If you're having trouble with bullet set-back you might want to take a look at the diameter of your powder drop / expander tube. You can easily polish it down if it's oversize and get smoother operation as a bonus. I don't have a specific dimension to tell you to look for but I would imagine that anything over .3555 - .3560 would be suspect. FWIW my Dillon dies leave my loaded 9mm rounds with a bit of a "waist" in the case below the bullet, I've never had a bullet set-back issue either FWIW. Link to comment Share on other sites More sharing options...
RC1 Posted November 2, 2004 Share Posted November 2, 2004 I started off loading to 9mm major on a 650 about a year ago, and had to go through the same learning process Here is a quote from one of the forum members (TBF) that helped me a lot. "It's the fit of the brass that holds the bullet, " crimp " is really not an accurate term for autoloader ammo IMHO, just remove the bell you put in for bullet seating. Be sure your sizing die is screwed in all the way when shell plate is in up position." I even went so far as to get the Lee under size die. This gives me plenty of case tension and I have never had an issue with setback. I am also using 125gr zero jhp's. Rick Link to comment Share on other sites More sharing options...
Newguy Posted November 2, 2004 Share Posted November 2, 2004 I haven't checked the crimp on my loaded rounds -- including 9mm open rounds -- in years. I just run my finger between the bullet and the case mouth to see if it feels smooth. The shiny spot on the case mouth where it meets the bullet should be about the width (thickness) of a fingernail. Rick is right -- it's the sizing die that determines case tension and whether the bullet will be held in tight. All the crimp should do is remove the bell from the case. I think there was an article in Frontsight a few years ago about not crimping at all. BTW, apart from the sizing die, you might want to make sure you're not belling out the case mouth too much. Link to comment Share on other sites More sharing options...
benos Posted November 2, 2004 Share Posted November 2, 2004 The crimp die has nothing to do with bullet/case tension. And it should never be adjusted to "add" case tension to the bullet. The crimp die's only function is to remove the flare applied by the flaring portion of the powder funnel. Nor, within reason, does the sizing die control bullet/case tension, because in straight-wall pistol cases the sizing die is designed to re-size the case mouth to a dimension smaller than it eventually needs to be, before seating the bullet. So technically it is the neck-expander which controls the bullet tension. In Dillon presses, the neck expander is the part of the powder funnel - the straight, cylindrical part of the powder funnel that first enters the case mouth before the case touches the flare (tapered) part of the powder funnel. The neck expander part of the powder funnel re-sizes the inside of the case mouth to the correct dimension (in theory). So the sizing dies squeezes down the neck too much, then the neck expander opens the neck back up to the correct dimension. As mentioned with the 9mm seated long, this relationship is critical. A much better solution is to turn down the neck expanding portion of the neck expander .001 - .002" on a lathe. (Rather than overworking the brass by initially sizing it down smaller than it should be. Although in some instances this may seem to help because of the 'springback factor" of the brass.) be Link to comment Share on other sites More sharing options...
smokshwn Posted November 3, 2004 Author Share Posted November 3, 2004 Thanx for the replies. I realize the crimp does not hold the bullet, but when I was getting setback I didn't really know what else would help to stop it. Brian Just got out the calipers and took a couple of measurements. Case size after resizing .375. I am belling to .390 (dillon manual suggests .020). The expander on the funnel .353, and my final crimp is .375. Does all this sound Kosher? I did load about 30 rounds and hand cycle them through my gun a half dozen times with no changes in OAL so I think maybe I was getting a little crazy with the thumb pressure. Link to comment Share on other sites More sharing options...
Little Bill Posted November 3, 2004 Share Posted November 3, 2004 It sounds like you understand that you basically don't want any crimp. You only remove the flared portion of the brass. For me, that tends to be .378ish. I like to run a set of calipers starting 0.1 from the mouth, to the end of the mouth, and see if it tapers in or out, or stays about the same. I try for .001 of taper. (I watched BE's video where he explains this well.) Next, if you have any bullet set-back issues, you should switch sizing dies, IMO. I would go to the Lee Undersize die or the Hornady die. I use the Undersize die on my 9mm major, and I don't worry about bullet set-back. I don't have any cases fail the case gauge for brass issues using this die either. Link to comment Share on other sites More sharing options...
DougCarden Posted November 3, 2004 Share Posted November 3, 2004 Sounds like you have it. As far as belling the case, you only need to bell the case enough to start the bullet into the case(jacketed- a little bit, a little more if you are loading lead,) you dont want to shave any while seating the bullet. I am at the point with 9mm that I look at the crimp while looking into a light, and adjust it until there is no bell left and the case mouth is smooth. I was trying to hit the magic number everytime with the crimp, and couldnt find the magic number. Good luck, DougC Link to comment Share on other sites More sharing options...
MoNsTeR Posted November 3, 2004 Share Posted November 3, 2004 Has anyone thought of shortening the Dillon expander to fight setback? Picture the powder funnel/expander thingy, it's got the rounded bit at the end, a straight section that expands, then an angled section that flares. If the straight section is longer than the length of bullet that's in contact with the case, then that means there'll be a length of expanded brass behind the bullet that it will easily push into. If you were to shorten the straight section of the expander, say to the exact length of the bullet/case mating length, the case inside diameter just behind the bullet would be tighter and setback would require more force. Did that make sense? Link to comment Share on other sites More sharing options...
smokshwn Posted November 3, 2004 Author Share Posted November 3, 2004 It makes sense to me. BTW, I polished the hell out of my expander with 2000 grit polish by chucking it in my drill and turning it in a tshirt. I have loaded another hundred rds. crimp at .375. the bell is just disappeared with the slightes hint of taper at the case mouth. So far the no set back with thumb pressure. Crossing my fingers for good chrono numbers tomorrow. Thanx for all of the help. Brian, I love this place. Thanx to you as well. Craig Link to comment Share on other sites More sharing options...
MoNsTeR Posted November 3, 2004 Share Posted November 3, 2004 Here's a quick'n'dirty not-to-scale rendering of what I had in mind... Link to comment Share on other sites More sharing options...
Dan Burwell Posted November 4, 2004 Share Posted November 4, 2004 Monster, I am not sure how much that would help with bullet tension. I think brian's idea about turning down the diameter like this: Sorry I stole your pic to better illustrate Brian's Idea. I think you'll see how this combined with an undersized sizing die should give you more than enough tension. IMHO a U-Die with this funnel would be the ultimate set up for anyone with a "tight" chamber. Dan Link to comment Share on other sites More sharing options...
MoNsTeR Posted November 4, 2004 Share Posted November 4, 2004 Right, that can help too. I had actually been thinking of combining the two mods. I guess the question is whether reducing the diameter is good enough, since it's much easier to accomplish. Another added benefit of a shorter expander would be less resistance in operating the press... Link to comment Share on other sites More sharing options...
benos Posted November 4, 2004 Share Posted November 4, 2004 All looks good to me - especially those great pics! I did load about 30 rounds and hand cycle them through my gun a half dozen times with no changes in OAL so I think maybe I was getting a little crazy with the thumb pressure. That sounds prefect. be Link to comment Share on other sites More sharing options...
Patrick Sweeney Posted November 5, 2004 Share Posted November 5, 2004 To determine if you need to use a tighter sizing die or turn/polish down your belling stem, measure the inside diameter after sizing but before belling. If you find your brass (in this case 9mm) has an ID of .350" after sizing but before belling, you don't need more sizing. Polish the belling stem. If, however, you find that your brass ID is .353" after sizing, then polishing the belling stem won't help. And shortening the belling stem is a good idea, but only if the diameters work out as outlined above. Link to comment Share on other sites More sharing options...
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