Press and die problem

[BJung]

I am having trouble seating my bullets the same so I can test accuracy based on seating depth.

I'd carefully seat my bullet so the OAL is determined. I lock everything down and start seating (not crimping) the bullets. I measure each on and the OAL varies by .001" or so.

Am I doing something wrong?

[BK7saum]

First of all, what kind of bullets, rifle or pistol, cast or jacketed, caliber...etc?

if my cartridges maintain a +/- 0.010" variation, that is usually good enough. Noses/tips vary. the Base to ogive measurement will be more consistent. Provide ALL the specifics and we can provide more help.

[rbuck351]

If you're getting + or - .001 you are doing well.

[dverna]

IMO you are worrying about something that will not matter.

When experimenting with seating depth I use increments of .010". A difference of +/- .001" is nothing to be concerned about.

[lightman]

My opinion is that a variation of .001 is very good. Measure some factory loads and you probably will see more than that.

[Bazoo]

Measure from the ogive instead of the point and see what runout you get.

[jmorris]

^

This.

I can open a new box of SMK’s and OAL of a hand full may differ by .004”, all the same if measured from the same point along the ogive, to the base.

[BJung]

Sorry, I should have included more information. I am loading 40-160gr TC bullets. The die seating stem is flat. I want to separate my fixed load by .01" exactly but the OAL floats =/- a few thousands. I've tried turning the case and seating slightly and then pumping the handle a few times. I've even just loaded a few and then measured them and I still have a variation.

[gwpercle]

Sorry, I should have included more information. I am loading 40-160gr TC bullets. The die seating stem is flat. I want to separate my fixed load by .01" exactly but the OAL floats =/- a few thousands. I've tried turning the case and seating slightly and then pumping the handle a few times. I've even just loaded a few and then measured them and I still have a variation.

Except for some highly specialized seating tools ... + / - .001" is as good as it gets . There is usually that much "slop" in the press linkage ... which is there because of tolerances and the handle and ram must be able to move up and down w/o binding .
What are you seating them with . One of the most consistent seaters is the one from a Classic Lee Loader ... why ? No linkage = no tolerances = no slop = no variation .
A Precision Arbor Press Type Seating Tool like the one by K+M Precision Reloading would possibly do better www.kmshooting.com
See Reloading Best Arbor Press at their web site .
Gary

[Shawlerbrook]

What they said above. To get better accuracy than that you would need to go the benchrest Shooters route with an arbor press and custom dies.

[Tim357]

Sorry, I should have included more information. I am loading 40-160gr TC bullets. The die seating stem is flat. I want to separate my fixed load by .01" exactly but the OAL floats =/- a few thousands. I've tried turning the case and seating slightly and then pumping the handle a few times. I've even just loaded a few and then measured them and I still have a variation.

How do they shoot?

[super6]

What press are you having trouble with? I had a rcbs turret and was sloppy and not repeatable, Got rid of it. If your getting .001 In deviance keep on keeping on.

[414gates]

Am I understanding correctly that you're chasing 1 thou AOL precision on a pistol bullet ?

[Bwana John]

If you fill the cup on the seating stem with epoxy and press a lubed up with release agent tip of the exact projectile you use into cup, you "might" get a little more precision.

[Taterhead]

Seating depth with vary. That's normal. Brass flexes some under the forces of seating and will spring back slightly when the ram is lowered. Each case will vary slightly in this regard. If varying by 1 thou, you're doing VERY good and I wouldn't chamge a thing.

[Noah Zark]

0.001-0.002" is typical measurement uncertainty for a caliper and operator.

You're doing really well if that's the sort of variation you get.

Noah

[Gunners Mate]

A long while back in Houston some of the best bench rest shooters in the world were shooting inside of an old Concrete Plant / Warehouse they took the wind out of the equation, I know Hart of Hart Barrels was one the guys shooting there and there were some other barrel makers shooting also, anyway long and short of they claimed Consistent Neck Tension had more to with accuracy and that inconsistent neck tension was the #1 reason for those score wrecking flyers. If all else is equal in your loads and your getting that odd duck chances are neck tension is your culprit.
Here is the artice its a good read
https://precisionrifleblog.com/2013/...ifle-accuracy/

[414gates]

This is a pistol bullet as far as I can tell.

[BJung]

I'm back. I have a series of testloads with seating depth problems. The first set was cast 40-170 TC Lee bullets. The seating depth varied +/- .002" and I wanted it exact. In the end, I left the variations as they were. I haven't shot these yet. The second set was 40-160 LHP Mihec cast bullets. I used lead from the same indoor range that uses primarily .22lr lead. The cast bullets were poured with a constant temperature and the lead was swirled into the molds. All bullets were consistently 160gr. I have a good load for this round at 1.131" OAL but am waiting to shoot it at various seating depths as well. Currently 4/5 shots group at 1" at 18 yards. I haven't shot testloads with varying seating depths yet.

[414gates]

You're getting worked up over an inconsequential seating depth variation in a lead pistol bullet.

Firstly, the platform, whatever pistol it is, is only as accurate as you can hold it. Pistols are not accurate by design. The slop in the parts alone means things don't perfectly line up shot to shot.

Secondly, accuracy is a relative concept. For me, accuracy is consecutive hits on a six inch plate at 500 yards. Which your bullet can never do.

You are using lead bullets. These have been lubed. You run them into the seating die, depositing lube on the way, and over time, it accumulates, causing an inconsequential seating depth variation. it doesn't matter.

Third, the variation in powder charge is more important than one or two thou seating depth.

You're wasting your time worrying over minor variations in seating depth of a cast bullet in a pistol caliber.