Hi all:
Heres the deal. The press is a 550 B Dillion. Dies are Texan 308, and are cleaned. Press is bolted down and does not move. Dies are tight and locked to the press with the die nuts. I set a bullet on the case mouth and run it up into the seat die. When seated round comes out of die I check the OAL. OAL varies as much as .025. When measured, the bullets and cases each vary a little each in their OAL, but does not come close to equaling the .025 for total OAL. This is totally unacceptable for accuracy.

Constructive comments...

Thanks


GT

Are you using a comparator? A comparator is a device that measures the OAL from the ogive of the bullet rather than the tip. Measuring from the ogive is a bit more accurate than measuring from the tip of the bullet.

I use this one.
http://www.sinclairintl.com/cgi-bin/category.cgi?catego...em=09-600&type=store

There are many kinds
http://www.sinclairintl.com/cgi-bin/category.cgi?category=RESDTCO&type=store

I don't use the blue reloading equipment. I am sure others will weigh in.

This constructive enough for you?

ZM

#1, the case length has nothing to do with the OAL
#2 there are 2 types of seater plugs (the part that contacts the bullet)
#2a, one uses a ring that contacts the bullet near the ogive, this type keeps the "distance to the lands" consistant, but let's the OAL run wild.
#2b, the other contacts the tip of the bullet, this type holds the OAL consistant, but lets the "distance to the lands" vari.

For accuracy, most shooters prefer that the distance to the lands remain constant, as long as the OAL dosn't interfere with magazine usage.

Gt1:

Are you loading a coompressed load? If so the bullet may be springing back in a not so tight neck. I recomend a taper crimp die in station 4. Another factor is there may be slop in between the press frame and the toolhead. You have a number of varibles.
Longshot

quote:

Originally posted by GT1:
... When seated round comes out of die I check the OAL. OAL varies as much as .025. When measured, the bullets and cases each vary a little each in their OAL, but does not come close to equaling the .025 for total OAL. This is totally unacceptable for accuracy. ...

Hey GT, You are getting some excellent input from everyone above.

Remove the Seating Stem and stick a Bullet into it. If it wobbles then the Tip is what is hitting and you will never get proper Seating. You will either need to modify the Seating Stem or contact the Manufacturer to see if they can supply a Seating Stem for a sleeker Ogive.

Also agree about the Compressed Loads could be a problem.

It sounds like you sat down and actually measured some Bullets from the Base to the Tip. And I agree there is normally some variance due to the Final Forming operation. But there should not be 0.025" in the Bullet alone, unless you are using some extremely cheap bullets. Maybe FMJs?

I'd suspect you are seeing some Tolerance Stacking, or Variances adding together.

Zeke mentioned a Bullet Comparitor and if you have not purchased the Sinclair already, you can use a "Socket" out of your Tool Box to do the same thing. Just get the largest Socket you have which will not slip past the Ogive. Then use it to measure from the Ogive to the Base(OtoB) on individual Bullets.

Set 5-10 Bullets aside that measure the same OtoB and try reloading them. Then measure the completed Cartridges using the same Socket to get the Ogive to CaseHead distance(OtoCH). Do not measure from the Tip.

If you have more variation in the OtoCH measurement than in the OtoB, then the problem is either something previously mentioned, the Neck Tension on the Cases, or you are being inconsistent with the stroke you use on the Dillon.

Best of luck to you.

Ok, so maybe I'm a bit ignorant but I've never heard of Texan dies? What are you loading the ammo for, what kind of bullets are we talking about? How does the ammo shoot? It sounds like you may be loading blasting ammo, if so, the tolerances are fine, maybe even for hunting ammo. For match ammo, I would think a set of match or neck dies along w/ a good single stage press to have a bit more control of each process. The other guys have given you good info. on bullet seating.

Are you trimming your brass?

If you are loading lead tipped bullets they may be distorted in packaging and handling. It's better to use a comparator (as described above) to measure to the ogive. IMO, it's better for any bullet type.

quote:

Originally posted by Tailgunner:
For accuracy, most shooters prefer that the distance to the lands remain constant, as long as the OAL dosn't interfere with magazine usage.

Yup. I cannot trust the OAL cause I have measured bullets, and the actual bullet length is not consistent sometimes. I measured some .375 Accubonds, and they varied from over 1.390 to under 1.380. The length from the ogive to base of brass is whats important for consistent distance off the lands, and using a seater that pushes on the ogive to seat. Hot Core showed me the way of the socket. I use a craftsman socket that stops on the ogive for ammo measurement. Having bullets that have a consistent ogive measurement is important. Like mentioned earlier, your only limitations on basing your measurements off the lands is fitting rounds in the magazine.

Heres an example. My mag box for my 375 RUM will hold rounds that are 3.635 OAL. That is still miles away from the lands with those accubonds, cause I can load rounds with a 3.800(give or take) OAL and still be .047 off of the lands.

Of course all of the other basic stuff like making sure you get to the end of your stroke for each round is important too. Hopefully that wasnt too confusing.

Great info all. This is not a compressed load. This is basic blasting ammo for my G3's. In this specific application, I am pulling bullets from Indian 308 ammo, altering the load and reseating the bullets. Accuracy is always important. I do however understand that sub standard components can give sub standard results. The comparator comment with the
socket deal will be tried TODAY. Excellent comments!!! Measuring from ogive to base is the way to go, my bad. I will also check that seating stem. I bought these Texan dies about 30 years ago. No dought they are out of buisness, but the dies are still in good shape.
No spring or deviation in my press. Just a couple of thousands when the base plate (that holds the cartridge) bottoms out on the dies and moves the die block up a little.

Thanks All


GT

Hey GT, Just thought of one more thing you can try.

After you have the Test Bullets all Seated and you do your OtoCH checking, if there is still a variance, try this: Rremove all the cartridges from the Dillon and just run the ones you just checked for variation through the Seating Die "again".

I have a RL550 also, and when the toolhead does move in the top of the press, it is not enoough to cause a problem. Mine moves just like yours does. If you really wanted to be anal about that, get a pair of sheet metal spark plug gappers, and find the right thickness, and shim both sides of the toolhead. Actually, you probably could get away with one set, just cut the gapper in half longways with a pair of tin snips(scissors might work if the sheet it thin enough.

Check your dies, and if they dont seem up to your standards, replace em with a set of reddings or RCBS. They both make micrometer hand adjustable seater dies, the RCBS even has a window cut in teh side so you drop the bullet in the window halfway through the stroke, and it rides a collet up to the seater. I believe the comp Redding seater has a collet also, but no side window. Both are fairly expensive, the Redding more than the RCBS.

To be honest with you, I use the plain jane redding seater, and I get excellent results. it is hand adjustable too, just without the micrometer.

I did find one problem yesterday. The seater is touching on the end of the bullet and not on the ogive. I will try the socket on the ogive maybe today. (I have oil to change in a vehicle and some of those CenterFire Systems mags I ordered need cleaning up.) Right now my Dillion is set up on 357 mag for my Coonan.

Lots of good comments guys.

Zeke if you read this I would like to know why you don't like the "blue reloading equipment? Just to see if your thoughts might be similar to mine?


Thanks

GT

Have had similar problems with a Lee .22 Hornet seating die . Some projectiles ok , others RS . Just a crap design .Ordered a Redding seating die which must be coming by snail .

quote:

Originally posted by GT1:
Great info all. This is not a compressed load. This is basic blasting ammo for my G3's. In this specific application, I am pulling bullets from Indian 308 ammo, altering the load and reseating the bullets. Accuracy is always important. I do however understand that sub standard components can give sub standard results. The comparator comment with the
socket deal will be tried TODAY. Excellent comments!!! Measuring from ogive to base is the way to go, my bad. I will also check that seating stem. I bought these Texan dies about 30 years ago. No dought they are out of buisness, but the dies are still in good shape.
No spring or deviation in my press. Just a couple of thousands when the base plate (that holds the cartridge) bottoms out on the dies and moves the die block up a little.

Thanks All


GT

I think your post is the problem or a contributor. You said you are pulling the bullet and changing the load and reseating. If you do not run the neck back in a die after pulling bullets they will have sloppy and inconsistent fit.

I noticed you said you were pulling the bullets from loaded military rounds, then reassembling after making your desired changes. Did you go back and neck size the case before reassembling. This is essential if your expect to have much, if any neck, tention on your reassembled rounds.

Good comments... Dwight/B1878/all. I tried to respond this morning before I went to work (5:00am) but accurateloading.com would not accept my reply for whatever reason...
Just one of those things that slipped my thinking... If the bullet is pulled, the ID neck can be no smaller (at that time) than what just went thru it. Hence, no bullet retension.

Note taken...

Just wish there was more hours in the day....


Thanks guys


GT