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Posted: 5/22/2008 7:44:59 PM EDT
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I just cranked out my first mass production of 9mm (500) and noticed that the OAL varied as much as .010, I checked everything and it's all tight ? I started with a OAL of 1.135 and the majority of them are 1.142 the high end is 1.145 ? I called Dillon and they said that it may vary .016 I personally think that is alot but I am quite new to reloading, I know there is a lot of flex in a progressive vs. a S/S so I have to ask is there a fix or is this normal ? I am using 124g Win bullets and mixed headstamp brass |
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I remember a similar topic came up 3 or so months ago. The variance is usually because of diffrences in the ogive of the projectiles and the seating stem contacts the projectile in different places for differnt individual projectiles. A simple test ot verify this is to seat 5 or so bullets with the seating stem set for seating truncated cone bullets, so it'll contact every bullet from the top of it, not further down on the bullet |
| Just in case, also check your shellplate to make sure that it's not too loose. Loosen up the set screw, and then tighten the large center bolt finger tight so the shellplate won't turn, then back it off just a bit to allow the shellplate to turn, and then tighten the set screw. You should be able to just easily turn the shellplate with your thumb but not have any up and down wiggle in it. |
| There is a very slight amount of wiggle in the shell plate so I tightened it up I also noticed some play in the toolhead so I did some searching and found a Toolhead Clamp and was wondering if this would help tighten up my OAL issue ? |
Sir, while I've not used the tool head clamp you have linked to your post I have used shim in the tool head to press fit to take up some of the slack when I'm concerned about cartridge OAL variations usually only with match rifle cartridges. For pistol cartridges the OAL variation you are concerned is largely inconsequential as long as the cartridges will fit in the magazines you intend to use them in and will reliably feed in your pistol. As mentioned by most of the other responders to your post the variation is largely due to differences in the shape of the bullet and therefore the point of contact with the seater plug and the bullet. NBD in my humble opinion, 7zero1. |
| I am not to concerned about pistol but when i start loading 308 rifle rounds I believe that variance would affect accuracy or am I wrong, I am not a match shooter by any means but I get pretty anal over things sometimes and strive for perfection but if this is the best I can get and the .010 OAL variance in pistol and rifle wont affect accuracy then I will accept that and move on |
Sir, that's why I mentioned in my previous post that I shim the fit of the tool head on to the top of the press. Cartridge OAL, in the context of the proximity of the bullet ogive distance from the rifle chamber throat can be important depending on the type of bullet you are using and the design of your rifle throat chamber. That's why competitive shooters use match bullets, ie: the ogive variation between bullets of the same lot are not generally measurable by conventional tools that most of us have. What is important is to measure the throat and use a comparator to determine the relative distance you want to place your bullet during the seating stroke of the press. HTH, 7zero1. |
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If you check with Dillon, they will tell you that the toolhead needs a little play for all of the stations to set correctly. I would suggest you get a bullet comparator to measure the bullet ogive to base and forget about OAL. If you are only trying to have consistent OAL, you can have variations in ogive length which is where your accuracy comes from. OAL is irrelevant (as long as you are mag length or less). Having consistent bullet lengths where they intersect the lands is what you are looking for. Look on midway for the Hornady bullet comparator. |
I concur. I've talked with Dillon at length about this for both my old 550B and current 650 and they state emphatically that the toolhead needs to 'float' for proper function of their presses. |
I may look into one of these to correct this or am i making to much out of this ? like I said I am not to concerned about pistol but rifle I think may be a issue or is it ? |
| Depends upon how much you want to do in the name of accuracy. I'm not a BR shooter so my setup is fine the way it comes from Dillon. If you are at the point of weighing your primers and turning your bullets to get the last little bit of accuracy, then the sky is the limit. |
If you're looking for the same OAL on each round, be prepared to adjust the seat die for each round. Even match grade bullets vary in length. Check length by the ogive. Eddie |
| I really don't want to be weighing primers and rolling bullets between panes of glass and seating each round by itself, I plan on loading for my SA XDSC 9mm and my SA M1A I may load some match rounds for my Savage 10 FLP but that won't be that many the other two I go thru quite alot of ammo and don't plan on living at the bench so I will do my best to maintain a acceptable OAL for the plinking stuff and the match I will do by itself and see how it goes |
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