Seating repeatability issue

[captnmo]

I'm new to reloading and am reloading 308 in a Lee Press. I'm having issues with the OAL being consistent. I'll take an empty round and seat it in small increments to get the OAL that I want (2.800 to be specific). I leave it alone and then measure my OAL on every load after that and they're getting shorter. Only by a little bit but in about increments of 0.005 each time to where I have to start over with the die.

Is this just because Lee's cheap and that's what cheap dies do? Or is this something I can fix? Or is this to be expected and keep adjusting as necessary?

 

[Tripwire]

Re: Seating repeatability issue

Where did you get your instruction to measure bullet seating via COAL.....

Is there an evil conspiracy somewhere that sends every FNG down the pipe with that malpractice..??

 

[Tomekeuro85]

Re: Seating repeatability issue

Since you're new, you may not know that the tip of each bullet is usually pretty inconsistent.

So although they're all seated the same, the COAL may differ.

Look at the sticky posts at the top of the reloading forum before you begin, they're extremely helpful.

 

[shoot4fun]

Re: Seating repeatability issue

Measure a box of the bullets you're using to roll those loads.
I'll bet you find you difference!
Oh, and the .005 could be coming from you calipers, unless they are a very good precision tool and you are well schooled in their use.

 

[captnmo]

Re: Seating repeatability issue

Yes, I'm familiar with measuring off the ogive and where it seats into the lands of the barrel. But I don't have the necessary tools to do that yet unless there's another technique I don't know about yet that I can accomplish with what I already have.

I know the tip of each bullet can be inconsistent, but if that were the reason I'm having this problem, why are they getting shorter consistently. I'd figure some would be longer, some shorter.

 

[captnmo]

Re: Seating repeatability issue

Regardless of whether I measure off the lands or off the COAL, if the die is creeping, doesn't that present a problem in both cases? I measured the bullets I've seated, and the caliper is consistent. The ones that were at 2.800 are still 2.800. Those that were at 2.765 are still at 2.765.

So I go back to my original question...

 

[shoot4fun]

Re: Seating repeatability issue

For a guy who says he's a reloading newbie you certainly seem to know everything.
OK, one last suggestion.
Take the seater apart and clean everything up. Look for anything that could be causing the seating plug to move around.
The design of the Lee seater is solid enough that you should it should not be moving, especially in. I could more understand it being the die if seating depth got longer due to maybe the threads beings oversized and allowing the stem to flex. I've used a lot of Lee dies over the years and never seen this issue from the die. Always from the bullet's inconsistency.
You have not said what brand of bullet you are using. Funny thing, I have measured Hornady Amax bullets that were all over the place but they shot great. I still would put most of this to the bullets themselves. BTW, there is .035" difference when you state 2.80" and 2.765".

 

[Fisky]

Re: Seating repeatability issue

Buy a bullet comparator and that will ease your mind a bit. I was all paranoid like you, getting variances as high as +/- 5 thou at times. Bought and checked them with the comparator, that dropped to +/- 2 thou or so.

I'd still like to get more consistent though. I don't know, do the competition dies seat more consistently? Or is it just operator error, not being consistent with the amount of pressure on the ram?

 

[notquiteright]

Re: Seating repeatability issue

capt-
how many times has the brass been fired?

I get that on virgin brass and stuff needing to be annealed.

My guess is virgin brass is 'springy' and gives some bounce as the die presses down.

Work hardened brass resists the bullet seating and then gives in a jump giving various OALs.

You can get virgin brass to be more consistent with a consistent stroke action, ahhh are you a married man???

Harder necked brass can use a bevel inside the neck to ease bullet entry. Use a nice slow stroke. Again are you married?

Now on being so anal as to measure the COAL at .005"-

I wouldnt sweat it too much, get consistent with how you pull down on the press arm and be happy. Dont know what rifle you are using and what chamber it has but 2.82" with most conventional bullets works well for me in a variety of rifles.

Good luck and use a nice and easy stroke.

 

[captnmo]

Re: Seating repeatability issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: notquiteright</div><div class="ubbcode-body">capt-
how many times has the brass been fired?

I get that on virgin brass and stuff needing to be annealed.

My guess is virgin brass is 'springy' and gives some bounce as the die presses down.

Work hardened brass resists the bullet seating and then gives in a jump giving various OALs.

You can get virgin brass to be more consistent with a consistent stroke action, ahhh are you a married man???

Harder necked brass can use a bevel inside the neck to ease bullet entry. Use a nice slow stroke. Again are you married?

Now on being so anal as to measure the COAL at .005"-

I wouldnt sweat it too much, get consistent with how you pull down on the press arm and be happy. Dont know what rifle you are using and what chamber it has but 2.82" with most conventional bullets works well for me in a variety of rifles.

Good luck and use a nice and easy stroke. </div></div>

Ha ha! Love it!

Fired once brass. I'm using Hornady brass and Hornady BTHP Match 168gr for a Savage 10FCP.

I did have them up to 2.82 but wanted to work up from 2.800 based on recommendations here on the relodaing depot.

 

[MitchAlsup]

Re: Seating repeatability issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: captnmo</div><div class="ubbcode-body">Yes, I'm familiar with measuring off the ogive and where it seats into the lands of the barrel. But I don't have the necessary tools to do that yet unless there's another technique I don't know about yet that I can accomplish with what I already have.

I know the tip of each bullet can be inconsistent, but if that were the reason I'm having this problem, why are they getting shorter consistently. I'd figure some would be longer, some shorter. </div></div>

If the loads are "reliably" getting shorter each new round through the die; something in the press, or die, or the seater stem is moving. So, can you tell us in your own words how you actually set the die in the press, and then how you dialed in the bullet seating position, and what you did to lock these positions in place.

Also note: If you measure OAL and measure Ogive-to-Base length and both are getting shorter, then is definately has to be the die+press.

Many seater dies press midway on the ogive (shape). Competition seater dies press as close to the shank as possible hoping to get the bullets in straighter, Only the competition dies are {accurate, reliable, repeatable} down in the 0.005 total variance range. In any event, you are going to see 0.005 variation in base to ogive=shank=transition, 0.005 variation in middle-of-ogive to base, and 0.005 variation in bullet-length. It is not just the tips of each bullet that can be inconsistent, each and every dimension can be inconsistent.

 

[rcamuglia]

Re: Seating repeatability issue

notquiteright has the answer.

Brass at different stages of work-hardening have different neck tensions. You probably see a different amount of effort when seating your bullets.

If you anneal your cases, you will feel bullets seat like butter. OAL will be more consistent.

 

[Greg Langelius *]

Re: Seating repeatability issue

NQR +10, absolutely; especially about not getting wound too tight. The choice is whether to accept the factory's QC standards, which may not be perfect but are still very practical; or chasing the rabbit down the hole and losing sight of the bigger picture.

Take it simple, and reality will eventually lead you to a truer understanding of which factors have a real impact.

Greg

 

[captnmo]

Re: Seating repeatability issue

Thanks all!

To answer Mitch, I screw in the die on an existing round until I feel it contact. Then I screw in the seater until I feel contact, and then back off just a bit. I then seat a bullet and measure the length. I'll repeat this last process until I get the COAL I want.

Don't know if that's how you guys do it. If you have better suggestions, let me know.

Thanks again for the input. I won't sweat it too much and get what I need to be measuring off the lands rather than the COAL.

 

[dammitall]

Re: Seating repeatability issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: captnmo</div><div class="ubbcode-body">Regardless of whether I measure off the lands or off the COAL, if the die is creeping, doesn't that present a problem in both cases? I measured the bullets I've seated, and the caliper is consistent. <span style="color: #FF6666">The ones that were at 2.800 are still 2.800. Those that were at 2.765 are still at 2.765.</span>
So I go back to my original question... </div></div>

That part in red above... so they are not creeping?
Or are they? That much variance sounds like a meplat to base measurement or bad bullets. I had some PRVI that were lousy like that. They were rocks.
Are you crimping and if so, what kind of crimp?
Crimping *may* change measured length if it's too heavy.
Neck tension? Compressed loads?

Ok, let's put OAL out of mind for a second.
Have a look at this thingy, a Hornady Lock n Load Comparator
http://www.midwayusa.com/viewProduct/default.aspx?productNumber=231904
With the correct insert you measure from ogive to base of the case. Put it on and zero the caliper. Measure, more than once. With two sets you can measure and sort bullets by bearing length for even more consistency. Sinclair makes them too.

You're not worried so much about actual precise measurement, just consistency for right now unless you're trying to match a factory ammo length. I matched the FGMM 175 and 168 for a start length until I found my load, then played with seating depth. I don't worry about velocity until it's accurate.

For seating I recommend a Redding micrometer match seating die, which seats from the ogive of the bullet and in no way touches on the meplat. If the bullet is cocked any at all, seating depth varies. Again, the Redding die helps prevent this. It was an improvement from the Lee seater. I am almost always within .002 from ogive to case base using SMKs.

Proper adjustment, consistent stroke, quality bullets will all make a difference as will the measuring instrument. Others may use slightly different tools or techniques but the principles remain the same. Consistency is the goal.

 

[captnmo]

Re: Seating repeatability issue

Sorry for the confusion. I was clarifying someone else's comments calling into question the accuracy of the caliper. The caliper is reading consistant after several re-measurments.

I'm not crimping and not sure about neck tension. How would I measure that? Just by the way it feels by seating the bullet?

Thanks for the gear recommendation. I've been looking at a few different competition die sets. I'll check that out.

 

[captnmo]

Re: Seating repeatability issue

Speaking of not touching the meplat, after seating the bullet, there's a ring around the nose. What's going on there?

 

[dammitall]

Re: Seating repeatability issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: captnmo</div><div class="ubbcode-body">Speaking of not touching the meplat, after seating the bullet, there's a ring around the nose. What's going on there? </div></div>

The ring is from the die. It should be maybe 1/3 of the way down the bullet with no tip deformation.
Actually there shouldn't be a ring at all from the die. If there is, very slight on close observation. I can't see one on mine. It shouldn't seat that hard.
Are you chamfering the necks? Also, if the die seating portion is sharp it might be cutting the jacket slightly. The Redding doesn't do that.

After you resize the brass and get it ready, after everything just before priming if you measured the inside of the neck diameter it would be something like .306 or very close and the bullet diameter would be .308 for a .002 neck tension.
It's a little tricky to measure with calipers but it can be done. You have to keep the caliper square to the casing and don't fully insert the i.d. measuring tails. Measure until you can repeat the measurement.

My brass neck is .306 close as I can tell with a Starrett 12" set. I check the caliper regularly with a 1" and 4" standard from a <span style="text-decoration: line-through">Starrett depth gauge</span> Tumico micrometer set. SMK 175 comes in at .308.
It's close enough.