.270 win overall length with 100 or 110 grain bullets

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scaleguy

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Hi all,

Im working up a good coyote load, and have a variety of bullets im going to try out. Im using IMR 4350 with some hollow points. From what ive read you want to drive them around 3100-3300 fps. Im just not sure what the ideal overall length is.

Thanks
 
scaleguy said:
Not sure what you mean by off the lands!
Click to expand...

You take a fired case and just bump this case in the sizing die enough to hold the bullet in place and still move back and forth. Seat a bullet "long" in the dummy test case and chamber it and measure the overall length doing this several times Doing this you are using the rifling (lands) to seat the bullet and this would be "zero" and then you seat your bullets shorter than this length.

Sometimes this can not be done on a long throated rifle because the cartridges will be too long to fit the magazine.

Read the link below and look at his photo in the first posting, BUT remember each rifle can be different for the best OAL. It is also rechecked as the rifle is used and has more rounds down the tube and corresponding throat erosion.

Topic: Jump Test Results

http://forum.accurateshooter.com/index.php?topic=3821963.0

Also "some" competitive shooters "jam" the bullet into the lands or rifling and the bullet is "into" the lands. Seating depth effects chamber pressure and this goes both ways, too far into the case raises chamber pressure and closer to the rifling can raise the pressure. So keep this in mind when working up your loads.
 
Last edited:
"...ideal overall length is..." Start with the length given in your manual. That'd be 3.145" for a 100 and 3.250" for a 110. You need to work up a load first. Adjusting the oal to just off the lands is one of the load tweaking techniques.
 
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