Uneven seating

[Matt304]

I have been reloading 444 Marlin, and have begun noticing that I am getting some seating alignment issues. I suspect it is hurting accuracy a good deal. I am using a Lee die set.

Basically, I flare the mouth just enough so that the bullet seats in a few MM with finger pressure. I try to stand the bullet as straight as I can with my eye, then seat.

The bullets are deforming the cases out a little, as in, you can see the bullet through the case and where its base begins. It is not bulging from crimping, rather just bulging from the bullet diameter in the straight case. Anyways, the bullets are not being pressed down into the case uniformly. Some make a visible ring around one side more than the other side.

I also chambered a few cast bullets touching the lands and took them out. Sure enough, the rifling was not engaging them evenly all around. A few lands did not leave marks on one side.

How can you prevent this uneven seating from occurring?

Thanks.

 

[BigJakeJ1s]

Use a better seating die. Look for dies with an alignment sleeve that lines the bullet up with the case mouth before seating it. All Hornady and Forster dies, as well as Competition series dies from Redding and RCBS have this.

Andy

 

[Sagetown]

Matt304 I just read a post about the same problem. I think they figured it was different case lengths causing the problem.??

 

[joneb]

It could be the die or the press, do you load other calibers ?
Does this happen with different bullet types ? I use RCBS dies they come two seating plugs one for round nose and one for flat I find the proper seating plug makes a difference.
I refaced the die receiver on my Rock chucker press this helped me with my problem which sounds like yours.

 

[04JRB]

I have the same issue with loading .40 S&W. I havent tried to change my setup yet or anything, I moved on to a different caliber for that day. I figured it was the bullets I was using, rainier from midway. I didnt have one issue while using winchester bullets, but those rainiers had to be lined up perfect to seat properly. Im curious now to find out if it was varying diameters of rainier bullets or it is something not right with my set up.

 

[ranger335v]

Your expander isn't enlarging the brass enough so the case stretches unevenly as the bullet expands its own way into the case. That uneven expansion is bending the mouth of the cases out of alignment with the body. NO seater can correct bent cases.

Get yourself a Lyman "M" expander die. It is THE cure for such problems.

 

[mkl]

You may be belling the case mouth more than necessary. I reload 45-70 with a Lee die set and don't seem to have your problem.

You want the minimum bell on the case mouth. "A few mm..." may be too much. I bell one mm or less; just enough so the seating process does not cause the case mouth to shave lead off the bullet. If you are using jacketed bullets, belling is seldom required if you have chamfered the inside of the case mouth.

I too, can see where the bullet slightly expands the case mouth after it is seated. That has never caused me any problems, so I don't worry about it.

 

[Matt304]

Your expander isn't enlarging the brass enough so the case stretches unevenly as the bullet expands its own way into the case. That uneven expansion is bending the mouth of the cases out of alignment with the body. NO seater can correct bent cases.

Get yourself a Lyman "M" expander die. It is THE cure for such problems.

Ranger335 seems to be describing the problem best. The flare is adequate enough, but below the flare the diameter is still a bit small. So the brass is stretching out over the bullet when pushed in, like a snake eating a rat.

I'm also wondering just how much of a "crimp" this acts as on the bullet, and if it's possibly causing higher pressures.

I do reload other calibers - no straightwalls otherwise except for 45LC, and I have a Hornady die for it. Those seat straight, but then again the brass isn't stretching like it is with the 444 Marlin bullets.

One contributing factor may be because I am using 330gr cast bullets, and they are somewhat long. So as the brass thickness increases more towards the base of the case, using longer bullets makes the tightness magnify the deeper it seats.

Sounds like I will be trying the M Expander die. Thanks.

 

[joneb]

What's the diameter of these 330gr cast bullets ? I think the 444 marlin was developed with 240gr bullets in mind which would explain the early 1:38 twist barrels. Does your Marlin have the micro groove barrel ?

 

[Ol` Joe]

Check your brass for uneven wall thickness. I see a lot of variation in most, both bottle neck and straight wall. The thinner side of the case will stretch more easily then the thicker and show the symptoms you describe.
I doubt it is the cause of much accuracy loss at shorter pistol/rifle range-100yds or so- but, it will show up once you get out a ways.

 

[rcmodel]

A few thoughts:

A 330 grain .44 bullet isn't exactly short!

1. It may be that the base of the long bullet is so far down in the case it is starting to run into the thicker case web, which causes deformation of the case.

Whichever side of the case is thinner will be the first to show signs of the bullet base pushing it out.

2. Try seating the bullet about half way, then lower the ram and rotate the case 180 degrees before you finish seating the bullet.
If there is any die mis-alignment, this will even out some of it on the finished round.

rcmodel

 

[243winxb]

1.A seating plug that fits the bullet well, will help the alignment issues. RCBS may still custom fit a seating plug to your bullet, dont know about Lee. Or you could try making your own custom seating plug using Brownells accra-glass bedding kit. Rought up the metal with a dremel tool so the compound can get a hold of it, tape it up, put some petroleum jelly on the bullet to keep it for sticking. 2. The bulging of the case where the base of the bullet ends is fairly normal. All types of full length sizing dies size down the brass way more than is needed, about .010" or more. This is done so all different makes of brass that have different wall thickness, will work when using different brands of brass. The expander opens the case mouth to about .002" to .003" smaller than bullet diameter. You dont see this in a bottle neck type round (308win.types) because the whole neck area is worked by the expander button. On the straight wall cases you would have to get custom fitted dies by sending brass, bullets, that you are going to use to the die maker. RCBS AND Redding will make custom dies. The buldge hurts nothing, it just looks bad. The bullet should be seated straight. You dies could be out of specification. This is where a good micrometer comes in handy.