seating depth ?

[cmysix]

Watch Eric Cortina'a video, IF I remember he says 5 thousand off the lands and then back by two as you develop the load.

 

[Schippergreg]

RCBS single stage press, Hornady seater die with micrometer top and digital caliper

Are you using a comparator to measure closer to the ojive or are you measuring to the tip of the bullet?

 

[rebs]

Are you using a comparator to measure closer to the ojive or are you measuring to the tip of the bullet?

measuring to the ogive

 

[rebs]

In order to seat bullets consistently the seater die can't remain static. More work yes for sure.

what do you mean by can't remain static

 

[William Vogel]

the reason I asked this is because I am having a hard time getting the seating depth exact. I am usually off by .005 in either direction.

I don’t understand why you are having a variation of more than +/-0.001 really more like 0.001 total. I’m no expert and I hold right at a thou.

 

[Chilly807]

You've likely got something going on with your seating pressure, ie way too much.. if you can see a dented ring near the tip of the bullet where the seater plug touches it, that's the problem. A compressed load will cause the same problem if it's too compressed.
The soft bullet is the first thing to give.

I believe Hornady includes a VLD seat plug with at least some of their die sets. I'd suggest coloring the tip of a bullet with a Sharpie, then place the removed seat plug against the bullet and give it a few twists. You'll see exactly where the plug is making contact. It should never be at the very tip of the bullet.

Most of my seater plugs have been removed and polished on the inside of the taper where they touch the bullet to break any sharp edges and smooth them.

Do you anneal? If not, as the cases get work hardened after several firings your seating pressure will increase. Eventually it'll get high enough to put a dent in the bullets, and your seat depth starts to vary.

As a comparison, I'm using a lowly Lee dead-length seating die with the 80.5 Bergers and have no trouble holding seat depth within +/- .001".
That's using annealed brass and a non-compressed load in a 223.

 

[Capt. Oblivious]

Have a look if the spring in your seating DIE isn't binding up when seating the bullet or that your seating stem isn't dragging on the inside of the DIE.

 

[Orr89rocz]

Why arent seaters made to where ogive meets full diameter dimension of the caliber used? Seem like it would solve a lot of problems with seat depth inconsistency. Nose length of bullets seem to vary alot more than base to ogive, so a seater contacting closer to tip will have more variance in seat depth than one contacting nearer the full diameter portion. I sort my bullets by oal and it seems to help since the seaters arent contacting near where i measure base to ogive oal

 

[Orr89rocz]

Nose geometry on the bullets I’ve sorted are usually pretty close, some of course vary to .003, the larger variance is in OAL I’ve seen as much as .010 in custom bullets.
Also, guys could use a comparator that is closer to the diameter of the seater stem… it’s not difficult at all.

Yeah sorted they are close. Out the box unsorted i can see oal difference of .010-.015. Granted some of that is meplat formation shape, you could spent time to square them off and be more consistent. Base to ogive on my hornady comparator doesnt vary more than .001 it seems. So id rather use dimensions closer to that

 

[Slowrunning]

I would do a test using a different press if you have access to one. If your press ram isn't returning to the same perfect height each time, you won't seat to a consistent depth.

 

[Shinbone]

For me, I had a heck of time getting consistent OAL from my Forster press and Redding seating dies. The main culprit was that the bullet would get wedged in the seating stem when being pressed into the case mouth, and would then get partially pulled out of the case mouth before becoming unstuck as the seating stem was withdrawn.

I spent a bunch of time messing with buying different seating stems, and then, additionally, lapping the various seating stems to fit each particular bullet I was loading, but with little improvement. I was thinking about taking the next step of bedding each seating stem for each bullet, but was balking due to all the time that would take since I like to experiment with many different bullets.

I then switched to an arbor press and in-line seating dies, and this solved my problem. Specifically, the in-line seating die design allows me to "break" the bullet loose from the seating stem with rotational force before withdrawing the seating stem. In other words, the seating stem would be free of the bullet before it was withdrawn, and the bullet had no chance to be partially withdrawn by the seating stem. I am now able to maintain OAL to .001"

 

[Webster]

I read that Berger 80.5 fullbore bullets are not fussy about seating depth. So if I am seating 20 off the lands what would be an acceptable plus or minus range to allow ? Could I allow three thousands or more in either direction ?

Describe the rifle. What's it used for. If it's a factory hunting rifle your wasting your time, just go with what shoots an acceptable group.

 

[ebb]

Is your press camming over? I was corrected lately that an over cam condition will give more consistent results. I see what they are saying, and it may be the best way. I am still testing to confirm.

 

[Murray Brook]

As a comparison, I'm using a lowly Lee dead-length seating die with the 80.5 Bergers and have no trouble holding seat depth within +/- .001".

I have several different BR bullet seaters and the Lee DL bullet seater is great. Definitely the best seater die that comes in a standard die set. JMO

 

[Steel Mover]

If you cut all your own chambers, the same way, then you develop a bullet seating process for your chambers and the type of throat you use on your reamers. So there is no one absolute answer for other people and their guns. I know that my match ammo is 100% prepared in all respects, the match chambers all cut to sweep a squared base on a squared bolt face, lugs and recesses, with 100% contact. The bullet lead is .003 to start. If shooting a factory gun, I do not advise that. My hunting or traveling ammo for airlines is .010.

 

[mikecr]

Why arent seaters made to where ogive meets full diameter dimension of the caliber used?

You want to push bullets into necks from against the super low angle nearest bullet bearing?
You would run into extreme wedging.

 

[Orr89rocz]

You want to push bullets into necks from against the super low angle nearest bullet bearing?
You would run into extreme wedging.

Idk maybe. Maybe not. If neck tension is really high it might not like it. But if you push by the nose on high neck tension the jacket can collapse/dent. You get rings. I would think a combination of right shape seater and closer to the ogive as contact point would be more consistent.

 

[rebs]

just a thought, if your seater stem is contacting the ogive the same for every bullet then when you measure BTO that number would be the same, a different number but they should all be the same, right ?

 

[JMAN80]

RCBS single stage press, Hornady seater die with micrometer top and digital caliper

What are you sizing with? Bushing die or standard FL sizer? I had a lot of variations in length until I switched to bushing dies with SAC bushings to obtain the neck tension I was after. Seating was very consistent using same Hornady seater you use. I have since switched to K&M arbor press and their chamber does.

 

[Straightshooter1]

just a thought, if your seater stem is contacting the ogive the same for every bullet then when you measure BTO that number would be the same, a different number but they should all be the same, right ?

That assumes the distance between the two are always the same. They're not.