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Hey Guys.....new to reloading. I have been reloading 45ACP and have my OAL set to 1.275. After running 50 through my Dillon Deal B press I measured one and it was at 1.270 and a few at 1.280 so .005 +_ How critical is that? I measured some factory 40cal that I have (sould be 1.135) and they are 1.120. they are PMC and shoot fine out of my Sig P229. Im thinking short is O.K but long is bad...but how much is to long? Thanks. Dave
 

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as long as they function in your weapon, you should be fine. As far as the O.A.L. differing +- .005. that could be the ogive of the bullet,,, not a problem
 

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Hey Guys.....new to reloading. I have been reloading 45ACP and have my OAL set to 1.275. After running 50 through my Dillon Deal B press I measured one and it was at 1.270 and a few at 1.280 so .005 +_ How critical is that? I measured some factory 40cal that I have (sould be 1.135) and they are 1.120. they are PMC and shoot fine out of my Sig P229. Im thinking short is O.K but long is bad...but how much is to long? Thanks. Dave
As for the 45 rounds, what type bullet are you using? If they are lead, you could be seeing a build of lube/lead on the seating stem, which will cause them to seat deeper. Short is okay to a point but to short can cause pressure elevation due to the confined space in the brass.
 

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Hey Guys.....new to reloading. I have been reloading 45ACP and have my OAL set to 1.275. After running 50 through my Dillon Deal B press I measured one and it was at 1.270 and a few at 1.280 so .005 +_ How critical is that? I measured some factory 40cal that I have (sould be 1.135) and they are 1.120. they are PMC and shoot fine out of my Sig P229. Im thinking short is O.K but long is bad...but how much is to long? Thanks. Dave
Why so long?
 

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Im thinking short is O.K but long is bad...but how much is to long? Thanks. Dave
In your situation maybe, but this is not necessarily true. A longer OAL may not chamber or cycle- this can be easily solved adjusting the seating die. Seating a bullet deeper for a shorter OAL raises pressure, be careful with this thought process, shorter can be OK but only up to a point.

In some instances you can jam a rifle bullet into the lands of the barrel by loading a long OAL and be OK, most likely it will generate higher than normal pressures and get you into the danger zone.

The moral of the story is keep your loads within SAAMI specs and you should be OK. Too short or too long can both produce undesireable results
 

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workonwood:

Nothing in this world is perfect and that goes for the shape of the bullets that come from a bullet manufacture. Often times the bullets in the box are mixed from several different batches where the bullets differ ever so slightly in the ogive of the bullets (Ogive is the shape of the nose of the bullet). So the length of the bullet can vary by some amount. For jacketed bullets the way they are made puts any extra jacket material into the nose of the bullet.

The seating dies push the bullet into the case during reloading from the tip of the bullet usually with a small cup that touches the bullet at the tip. If every bullet nose has a chance of being a slightly different shape then different OAL of the finished cartridge can exist. The key measurement should be made using a bullet "Nut" which rest on the caliber reference point on the ogive. Measuring the OAL without that tool can lead to the assumption that the OAL varies more than it really does. The tool is:

http://www.sinclairintl.com/reloadi...r-hex-style-bullet-comparators-prod34262.aspx

The way you use it is to use the OAL in the reloading manual on a test round and make sure that OAL cartridge feeds and chambers correctly in your gun. Next, use the bullet comparator on the test round and get a reference measurement. Use the gage on subsequent cartridges that are reloaded to see what the variation between them all really is. It should be no more than a couple of thousandths if your dies are clean and your press is set up correctly and the press and dies are a good ones. More consistency can be had by separating the seating process and the crimping process into two dies instead of one combo process.

LDBennett
 
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