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2scoops

more consistent AOL

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any advise or tips on how to achieve a more consistent AOL ? I'm getting a variation of 1.129 to 1.135 when i load my 9mm ammo. Running a 1050 with Ammobot, Mr bullet feeder, Redding competition seating die.

 

Could it be the bullet ? (147gr Extreme)

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35 minutes ago, 2scoops said:

any advise or tips on how to achieve a more consistent AOL ? I'm getting a variation of 1.129 to 1.135 when i load my 9mm ammo. Running a 1050 with Ammobot, Mr bullet feeder, Redding competition seating die.

 

Could it be the bullet ? (147gr Extreme)

:yawn: Sort by headstamp, use case lube. If that doesn't cure it, ditch the competition seating die. I never could get consistent oal using one of those.

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Go shoot it. If the gun groups well with your ammo, stop worrying about it right there.

 

The biggest way to cut your OAL variations by 75% is to sort by headstamp, which is the one thing onlt old retired folks care enough to do.

 

Chrono good? Shoot tight groups? Keep on loading just the way it is.

Edited by MemphisMechanic

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11 hours ago, 2scoops said:

  I'm getting a variation of 1.129" to 1.135"  

 

 

Nothing wrong with that for action sports - you shooting at tiny targets at 50 yards ?

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14 hours ago, Sarge said:

:yawn: Sort by headstamp, use case lube. If that doesn't cure it, ditch the competition seating die. I never could get consistent oal using one of those.

Same, Ive got a couple forsters and a redding (all rifle) and none of them worked well for me and the forsters leave marks on my bullets sometimes,and sometimes even rip the plating off.I've tried them a few times but I always end up back to my Dillon seating dies

 

It could be the bullets. The seating die probably isnt pushing on the tip of the bullet but pushing off wherever it makes contact. If the bullets arent uniform that could make your difference. But thats not the end of the world. The chamber is the same way It doesnt care what the tip is doing. So If it shoots well, shoot it.

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20 hours ago, 2scoops said:

any advise or tips on how to achieve a more consistent AOL ? I'm getting a variation of 1.129 to 1.135 when i load my 9mm ammo. Running a 1050 with Ammobot, Mr bullet feeder, Redding competition seating die.

 

Could it be the bullet ? (147gr Extreme)

 

I would not worry at all about .006" variation; as long as they all plunk in your barrel, that's not enough variation to matter.

 

If you really want to cut it down less, you could just sort out certain headstamps like CBC and Aguila that have more internal taper. That 147 Extreme bullet definitely gets into the taper on some of those headstamps, and it causes some OAL variation. Honestly though I think your bigger benefit there would be from not damaging the bullet base, more so than reducing OAL variation. 

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+/- 0.010" is perfectly normal

Measure OAL of your bullets

Measure COL of factory rounds

Get a seating stem that only contacts the bullet low on the ogive

If you are truly anal, seat a bit long, move the round to another press, and seat in small increments until you get your targeted COL

The only contacts for seating is seating stem to bullet and case head to shell plate, so variation must be bullet variation, different ram pressure, and press flexure

For a 6-20 moa Pistol, you'll never see any effect out to at least 50 yds.

As they say in meatballs, "It just doesn't matter."

Edited by noylj

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Thanks for all the replies. My issue lies in the extreme spread that I’m trying to manage for chrono. I’ve never struggled before and with new brass and jacketed bullets would usually get around 25 to 30fps spread on a minor load (147gr @ 900fps). Recently my extreme spread has risen to close to 70fps. Measured the charge weight on my FX scale (laboratory) and charge variance is really low. Only other conclusion is that the OAL is large. This also started when I started loading with an ammobot.

 

Will dig deeper to try and understand. Have also taken all your advise

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2 hours ago, 2scoops said:

 my extreme spread has risen to close to 70fps. 

 

Has that affected practical accuracy ?

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31 minutes ago, Hi-Power Jack said:

 

Has that affected practical accuracy ?

no but it's a 10 factor spread

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I could be wrong, but as long as it is feeding and not dropping hit factor I would think it would be ok.

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21 hours ago, 2scoops said:

Thanks for all the replies. My issue lies in the extreme spread that I’m trying to manage for chrono. I’ve never struggled before and with new brass and jacketed bullets would usually get around 25 to 30fps spread on a minor load (147gr @ 900fps). Recently my extreme spread has risen to close to 70fps. Measured the charge weight on my FX scale (laboratory) and charge variance is really low. Only other conclusion is that the OAL is large. This also started when I started loading with an ammobot.

 

Will dig deeper to try and understand. Have also taken all your advise

 

Even without knowing what powder you are using, my bet is that your 70fps ES is not a direct result of .006 difference in OAL.

I use range brass loading 9 major loads with the case very close to full. The near full case charge makes it easy to see the difference in case volume between head-stamps.

My bet is this difference in case volume with mixed brass is a much bigger factor to your ES than .006 OAL difference.

 

Other things in play with a big ES:

Variations in bullet weight.

Full sun light when you chrono

Try a different chrono. My last chrono was all over the place like this when I tried another and found out the chrono was really bad.

The powder you are using may not work efficiently at the specific load you are at. Try different powders for same PF or try upping the PF with current powder (be safe of course- ladder test, observe primers, etc.).

 

Like many have said already though, .010 variation in OAL is not a significant factor to practical accuracy (assuming your load is not on the edge of what feeds in your gun or contacting barrel leade).  Other than curiosity, I wouldn't chase .006 OAL variation. That isn't bad at all using range brass.

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