Dillon 750 Inconsitant Bullet Seating Depths

[ekraus]

Before I started shooting a PPQ SF and was shooting a P320 bullet, OAL wasn't much of an issue it ate anything. I had an issue at a match yesterday where the RNDS were jaming in the

mag. I went to a practice bay and noticed the RNDS were getting stuck on the ramp and in some cases were getting stuck in the mag. I am running Xtreme 135 RNFP 3.5g N320 at 1.150.

They appeared to be to long.

I checked 10 RNDS and there was a spread of .009. I am using a Hornady seating die with a micrometer (using it because of the ease of using different bullets). I stooped using the Dillon seater because its a PIA to set. The nice thing about the Dillon die is the the flip seating stem for different profile bullets. So I figure it could be several things giving the inconstancy.

Seating Stem , inconstant shell plate machining, loose shell plate (I have it tight), inconstant bullet profiles.

Or maybe me not going through the full stroke.

I am leaning towards the inconstant bullet profiles.

Looking for some other possible issues.

 

[RudyVey]

Are you using the same brass or is it a mix?

[Joe4d]

Id be surprised if they chamber at that length even if you got them out of the mags.  Walthers are known for having fairly short chambers.  Reduce your OAL down to at least 1.130 and you will probably fix the issues.
I dont have a very high opinion of Xtreme bullets,  but be easy to measure a handful.
Another issue,, we are dealing with a progressive press here, tool head gonna move a hair, shellplate a hair,  brass rim and groove varies a hair,, add all that up and .009 is pretty trivial.  Go at least ,020 shorter than your chamber.

[Blackstone45]

19 hours ago, ekraus said:

Before I started shooting a PPQ SF and was shooting a P320 bullet, OAL wasn't much of an issue it ate anything. I had an issue at a match yesterday where the RNDS were jaming in the

mag. I went to a practice bay and noticed the RNDS were getting stuck on the ramp and in some cases were getting stuck in the mag. I am running Xtreme 135 RNFP 3.5g N320 at 1.150.

They appeared to be to long.

I checked 10 RNDS and there was a spread of .009. I am using a Hornady seating die with a micrometer (using it because of the ease of using different bullets). I stooped using the Dillon seater because its a PIA to set. The nice thing about the Dillon die is the the flip seating stem for different profile bullets. So I figure it could be several things giving the inconstancy.

Seating Stem , inconstant shell plate machining, loose shell plate (I have it tight), inconstant bullet profiles.

Or maybe me not going through the full stroke.

I am leaning towards the inconstant bullet profiles.

Looking for some other possible issues.

 

I don't know if the Hornady micrometer seating dies are the same, but I use a Redding micrometer competition seating die. I was also getting variations in OALs, until I read that the redding die seats based on the ogive of the bullet (which is arguably the important part, as that's the part of the bullet that's going to come into contact with the rifling). So the OAL variations I was getting was because the bullet profiles were not consistent, but the die was seating them so that the ogive was consistently the same depth. Hope that makes sense, and hopefully that's what is happening with your dies too.

[ekraus]

My mistake not checking the OAL when using the new box of bullets.

But

What bugs me is I wonder if the Dillon seater is more accurate from RND to RND. There were several in the 200 I loaded the were in the neighborhood of 1.150, that's what led me to believe that ogive was different on the new batch of bullets.

The thing is I am relatively sure the molds for the most bullets aren't super precision. You can't expect precision when you are paying less then a dime per head when bullets for BR can cost a buck each.

But I am still wondering about the Dillon die. I was thinking about getting the Whidden Click Adjust lock ring, but its huge and may not work in the 750 tool head. Or maybe the one of the other clamp style rings. Easier then having to use 2 wrenches to snug the die down.

The real problem is with loading different bullet weights and manufactures made me go with the Micro adjust die.

[4n2t0]

Determine the max OAL by starting extra long and constantly shortening the round until it plunks and spins in the barrel. You should do this for every new bullet/barrel combo. As you found out, the magazine can also determine the OAL but usually that only occurs when your ammo is loaded fairly long.

 

As for the Dillon seater...I've tried most and it's as consistent as any other. I target 1.09 for my 9mm and I get approximately 1.088 - 1.094 with mixed range brass. That's good enough for me! I only use the flat nose side of the insert for SWC's. I prefer seating all RN, including RNFP, off the ogive. I don't like any of the micrometer seating dies but that's just personal preference and poor experiences, similar to the one you're currently having.

 

You can throw away a bunch of money chasing the "perfect OAL" or save a boat load realizing that it doesn't mean $hit. If the round chambers, fires and ejects call it good and move on to something more important.

 

 

Edited May 30, 2023 by 4n2t0

[Paul B]

Recently found out that bullet ogive can be a big factor. Shot a ton of truncated cone blue bullet 147 9mm in my x5 with no problems but they would not seat in the match barrel of my 9mm 1911. I had to shorten them. The same thing happened with blue bullet 230s in my 1911 .45s. One liked them and they would not seat in the chamber of the other. A bit shorter load worked. The interesting part is that the same bullets in jacketed form and the same length worked perfect in all the guns and they all fit the mags just fine.

 

Just a matter of fitting the bullet to the gun - plunk test could have saved me some time.

[CC3D]

my rule of thumb is if it's + or - .005 I don't worry about it. Your extreme spread of .009 would be within that and not a cause for concern. As others mentioned, shorten your AOL to avoid the mag issue.. As far as the ramp issue, that can be a consequence of your bullet length OR the bullet profile. My TSO hates truncated cones no matter what length I run them at and they get stuck on the feed ramp. 

 

Also be sure that you are using the correct seating stem for your bullet profile (some are flat, some are cupped, etc) as that can have an affect on inconsistent depth or even cause run out. 

[VortecMAX]

All of this has been discussed before, and all of this will be discussed again.

 

 

Mike