When seating bullets with my Lee seating dies my OAL are inconsistent. I find that when I dial the die in on a certain round to get the exact seating depth, the next round and all the rounds after that will vary up and down by 5 thou. Is this normal?
Incosistent OAL
- Thread starter lorne19
- Start date
- Location
- Prince Albert, Sk
Depending on the bullet type yes, If you can get your hands on a comparator and measure the ogive and not the tip, you may find that you are closer than you think.
Happened to me, now I never measure to the tip.
Happened to me, now I never measure to the tip.
As KT mention measuring the ogive is better then the tip. However even measuring the Ogdive will not give you a exact OAL every time because each die the bullets are formed in may not be identicle and usually have tiny variation. Take 10 bullets comparator it then average it this will give a better measurement to and from your lands and help you determine your OAL.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
What type of bullet are you seating?
Not all bullets are made well.
Jerry
Not all bullets are made well.
Jerry
I just took a piece of paper from my printer, not very heavy printing paper, and with my Millers Falls micrometer it measured .oo45" thick!
A difference of .005" on the tips of your bullets being loaded is absolutely less than nothing.
Why do people worry so much about miniscule things that mean nothing to their loaded cartridges?
A difference of .005" on the tips of your bullets being loaded is absolutely less than nothing.
Why do people worry so much about miniscule things that mean nothing to their loaded cartridges?
Presses flex more than many realize. Expecially at the low end of the range of forces that they deal with, when all the slack is still being taken up in the various components of the press.
This is a cause of inconsistent OAL, especially with compressed loads, that is often overlooked.
If you happen to have a seating die that has no built in crimper, you can eliminate the press as a variable by being sure that the shell holder contacts the bottom of the die very firmly and cams over (if it's that type of press). This eliminates press flex as a variable.
I've had press flex cause variable OAL in heavily compressed 30-06 loads (measured from the ogive not the tip) and this was with a Rock Chucker (one of the good 20 year old ones). Indexing on the seating die cured it.
Imagine what the variation in a less robust press might be?
Going off on a bit of a tangent, this also happens when trying to partially full-length-resize cases or "just size them enough that the lever or bolt closes'. Well I'm sorry to tell you that unless you're indexing hard against the bottom of a die, your 'sized length' is going to be all over the place. With PFLR it doesn't matter a bit, but if you're trying to get it to 'just fit' in a lever action, you may have problems if some cases offer more sizing resistance than others which is often the case.
Redding used to make (likely still does) a set of extended shell holders that allowed one to do exactly this in measured increments. Few people seem to understand what they're for to this day.
To the OP, I agree whith H4831 (almost always do...), a small variation in OAL is no big deal until you get into shooting tiny little groups from a bench.
This is a cause of inconsistent OAL, especially with compressed loads, that is often overlooked.
If you happen to have a seating die that has no built in crimper, you can eliminate the press as a variable by being sure that the shell holder contacts the bottom of the die very firmly and cams over (if it's that type of press). This eliminates press flex as a variable.
I've had press flex cause variable OAL in heavily compressed 30-06 loads (measured from the ogive not the tip) and this was with a Rock Chucker (one of the good 20 year old ones). Indexing on the seating die cured it.
Imagine what the variation in a less robust press might be?
Going off on a bit of a tangent, this also happens when trying to partially full-length-resize cases or "just size them enough that the lever or bolt closes'. Well I'm sorry to tell you that unless you're indexing hard against the bottom of a die, your 'sized length' is going to be all over the place. With PFLR it doesn't matter a bit, but if you're trying to get it to 'just fit' in a lever action, you may have problems if some cases offer more sizing resistance than others which is often the case.
Redding used to make (likely still does) a set of extended shell holders that allowed one to do exactly this in measured increments. Few people seem to understand what they're for to this day.
To the OP, I agree whith H4831 (almost always do...), a small variation in OAL is no big deal until you get into shooting tiny little groups from a bench.
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The bullet seating stem in your die is making contact with a point on the ogive of the bullets. Seating will be uniform when measured to that point. The variations you are seeing result from variations in the bullets, not from anything wrong with the die. Perfectly normal.
There are tools you can get to measure the distance from the casehead to a reference point on th ogive. There are two lengths which are relevant for you. One is overall length as it relates to the magazine of the rifle, if you are using the magazine. The second relates to the relationship between the ogive of the bullet and the leade of the chamber in the rifle.
There are tools you can get to measure the distance from the casehead to a reference point on th ogive. There are two lengths which are relevant for you. One is overall length as it relates to the magazine of the rifle, if you are using the magazine. The second relates to the relationship between the ogive of the bullet and the leade of the chamber in the rifle.
Depends on how consistent bullets are and what seating stem in the die you use.
0.005" should not affect accuracy but may affect feeding if you are 'on the edge' to be a little long.
Personally, I'm more concerned where 'tails' of my bullets are so I have consistent volume under the bullet; as long as I don't get them hit barrel's rifling...
0.005" should not affect accuracy but may affect feeding if you are 'on the edge' to be a little long.
Personally, I'm more concerned where 'tails' of my bullets are so I have consistent volume under the bullet; as long as I don't get them hit barrel's rifling...
I use a set of the Stoney Point - now Hornady - comparators and they work just fine.
