Not getting consistent OAL

[westernrover]

I'm seating .264" 120 gr. Barnes Match Burners over 27.5 gr. of H335 with a Redding seater on an RCBS single stage press. Without adjusting my seater, I seated the first one and measured it at 2.250" OAL. Barne's published data shows 2.220" so I continued to seat bullets. I found they varied by as much as +/- ten thou.

The Barnes data shows a maximum load of 28 grains and indicates it will be a compressed load. Figuring that I am compressing the powder, I backed off the seater by ten thou and seated all the bullets. Then I adjusted it in to seat a second time at 2.250". I'm doing 100. So I finished the second pass with the seater.

I attached my Sinclair comparator to the calipers and zeroed it on the first one. I found about half were that length +/- one thou. Another 40 or so were as much as 7 thou shorter. About 10 were about 5 thou longer. I sorted them into like OAL and packed them in MTM cases.

I have another 600 to load. What's going wrong?

I suspect it's the compressed powder that's pushing back. I have 8 pounds of this one and I'm not about to find another anytime soon. I can a seat a little longer. I'm limited by magazine length rather than throat. Even so, Barnes shows their 140 gr. Match Burner fitting over 27.6 gr. of H335 in 2.240" OAL. Again, I'm seating the shorter 120 gr. Match Burner over 27.5 gr. of H335 at around 2.250"

 

[troy fairweather]

Is this to the tip of the bullet or the ogive, make sure you have a good hard stop to be consistent or just camover. Could get crap in the seater messing things up.

 

[AJC1]

Are you using the same case as listed or one of comparable volume or one with less. If you case has less volume and a compressed load you may have to reduce the charge. Are all the cases the same headstamp fire formed in the same rifle.

 

[splattergun]

Are all cases the same head stamp or mixed brass? different cases will give you varying neck tension which can result in a smidgeon of springback in a compressed load.
As for me, I ain't gonna sweat a few thou's +- difference in mixed brass as long as the finished round fits both magazine and chamber/throat. I don't shoot well enough to notice any difference on target in the variable you're seeing.
Also, make certain your measuring tools are properly calibrated, and if battery-powered, have fresh batts.

 

[westernrover]

All the cases are once-fired Starline. I bought the brass new and fired it all in the same rifle. They were bumped a thou. Having been fired and bumped they have more volume than new brass where the shoulder is farther back. The necks were sized on a LCD.

I measured base of head to tip with a Brown & Sharpe dial caliper. That's where I got the OAL. After I noticed differences in the OAL, I used a Sinclair comparator on the same calipers to measure base to ogive or whatever the comparator indexes on. I'm comparing apples to apples but some apples are longer and others are shorter.

My press has cam-over which is new to me. I set the die up by closing the press all the way, screwing in the die to touch the shell plate, and fixing the lock ring. I adjusted the seating depth with the small adjuster on the top of the seater die.

 

[41 Mag]

Been there done that. One thing you might check is to see if there is any contact from the tips of the bullets to the bottom of the seating stam cup. If so you might be able to drill it out just a touch to clear.

Then again it could also be as you mentioned about the powder and push back. In that case if you have an ingraver or something similar that you can touch the loading tray or even an individual case to to settle the powder before seating the bullet. I've even used the threaded rod on my vibratory tumbler. Just make sure you have a finger or piece of cardboard over the top to keep the powder in. Once settled things should even out a bit more if the powder is the culprit.

 

[AJC1]

If your shoulders are the same and the case is the same make the next thing I would try is a drop tube to get better powder settling. You can also use an electric truth brush.

 

[bluejay75]

Clean the necks with a 264 bronze brush chucked in a drill. Depending on your loading regimen there’s a likelihood that you didn’t get all of Starline preservatives out of the necks. I had the exact same issue. When seating on a compressed load it seems like that stuff in the neck will stop a bullet as soon as you hit compression then will make the bullet give a little. If only some of your bullets have mild to moderate seating rings on them that’s most likely the culprit.

A mandrel die will solve it as well.

 

[243winxb]

What cartridge are you loading? The 6.5 Grendel compresses most powders. View attachment 1024831

H335 is a flattened ball powder . It will not compress as well as stick powder like IMR .

Bullets can be checked from base to ogive, to see if the bullets are causing the .012" difference in OAL.

A drop tube may help, as said above, but may not help with spherical powder ?

The tip of the bullets should not contact the seating stem/plug.

 

[Bob Meyer]

I have had the same problem, +- 10 thousands difference in OAL when loading 25-06 on my RCBS Ammocrafter press. Using the same dies and bullets I tried the same load on my Hollywood Senior press and found much more consistent OAL (I don't remember the exact variation, 3-4 thousandths I think). Who would have thought there would be that much difference between presses.

 

[243winxb]

Lee's Dead Length Bullet Seater is said to help with seating OAL. The bottom of the seat die contacts the shell holder. It acts as a stop & should remove any slop from the press? Comes as a set with the Collet Neck Sizer. https://leeprecision.com/collet-dies-6.5-grendel.html

I tested the collet in 243 but not the seater.

 

[243winxb]

Redding seater

The Redding Competition Bullet seat die can be set to lightly contact the shell holder, to better control OAL. (From Reddings Website.) I never used one.
This may not work on a progressive press? Each station may have a different deck height .125" + or - .

 

[JFrank]

All the cases are once-fired Starline. I bought the brass new and fired it all in the same rifle. They were bumped a thou. Having been fired and bumped they have more volume than new brass where the shoulder is farther back. The necks were sized on a LCD.

I measured base of head to tip with a Brown & Sharpe dial caliper. That's where I got the OAL. After I noticed differences in the OAL, I used a Sinclair comparator on the same calipers to measure base to ogive or whatever the comparator indexes on. I'm comparing apples to apples but some apples are longer and others are shorter.

My press has cam-over which is new to me. I set the die up by closing the press all the way, screwing in the die to touch the shell plate, and fixing the lock ring. I adjusted the seating depth with the small adjuster on the top of the seater die.

We keep our seater above the shell holder, no need or reason to touch or cam over. Ensure your seater top isn't bottomed out in the base. I just went through this with my SiL. Use a drop tube as mentioned above. But do go back also and color a bullet tip then cycle the press to mark where the stem is making contact. Again ya dont want the meplat to touch.
Please report back when you get it figured out

 

[AJC1]

If load compression is effecting your ability to get consistent seating depth I would shift to the next faster/more power dense powder i had on hand. In these current times that's not exactly easy but nothing good ever comes easy. In your position reducing the load may be the better choice but continuing the pattern will continue the result.

 

[bluejay75]

@AJC1 hes not going to get much smaller or denser than H335. I rarely if ever compress ball powders. They seem not to like too much compression.

And…he’s using Starline brass. On every cartridge I have tried it in the capacity is usually about a full grain less in Starline compared to commercial. He might just be out of space.

 

[243winxb]

https://www.redding-reloading.com/tech-line-a-tips-faqs/143-seating-depth-variation

Heavily compressed loads can create problems when seating bullets. Our Competition Seating Die is not a powder compression die. The excessive force required to seat a bullet on a compressed load can damage the die and may cause seating depth variations. Switching to a faster burning or ball powder may eliminate the need to excessively compress the powder charge.

 

[AJC1]

@AJC1 hes not going to get much smaller or denser than H335. I rarely if ever compress ball powders. They seem not to like too much compression.

H322 or reloader 7 would be faster. Those are the pivotal powders I consider real rifle. 1680 is kinda a 300bo powder in my mind. There are also gas system issues I know nothing about.

 

[Rule3]

What cartridge are you loading? .

What a "novel" idea! to actually list the caliber or cartridge for the non clairvoyant of us.
Like folks asking for a load for a 29-5 or such

 

[AJC1]

What a "novel" idea! to actually list the caliber or cartridge for the non clairvoyant of us.
Like folks asking for a load for a 29-5 or such

I guessed 6.5 grendel but might be 6.8. Those are the two that meet ar requirements of the seating depth wth a bullet weight that high. Good inital post information though.

 

[Mark_Mark]

+/- .005 is good for me. anybody else

bullet variations, were & how measuring, junk in the die…

 

[bluejay75]

+/- .005 is good for me. anybody else

bullet variations, were & how measuring, junk in the die…

I could live with .005.

 

[JDinFbg]

Lee's Dead Length Bullet Seater is said to help with seating OAL. The bottom of the seat die contacts the shell holder.

When I saw your post about Lee's Dead Length Bullet Seater, I thought this might be the solution for what I wanted to do for loading 45 Colt since I plan to use the Lee Factory Crimp Die to do the crimping. Unfortunately, I found out from Lee that their Dead Length dies are only offered in bottle-neck rifle cartridges. Their seaters for pistol cartridges all have a two-step crimp in them. Rats!

 

[splattergun]

When I saw your post about Lee's Dead Length Bullet Seater, I thought this might be the solution for what I wanted to do for loading 45 Colt since I plan to use the Lee Factory Crimp Die to do the crimping. Unfortunately, I found out from Lee that their Dead Length dies are only offered in bottle-neck rifle cartridges. Their seaters for pistol cartridges all have a two-step crimp in them. Rats!

Lee's pistol bullet seating dies have 2 crimp shoulders so you can seat and crimp in one operation. The 1st is a taper crimp, 2nd is for roll crimp. Depending on how you adjust the die, you can seat the bullet without any crimp, and whatever degree of taper or roll crimp you choose, per cartridge requirement, taper for autos, roll crimp for revolvers.. Lee also has a Factory Crimp Die to crimp after seating.

 

[dcloco]

Been there done that. One thing you might check is to see if there is any contact from the tips of the bullets to the bottom of the seating stam cup. If so you might be able to drill it out just a touch to clear.

Then again it could also be as you mentioned about the powder and push back. In that case if you have an ingraver or something similar that you can touch the loading tray or even an individual case to to settle the powder before seating the bullet. I've even used the threaded rod on my vibratory tumbler. Just make sure you have a finger or piece of cardboard over the top to keep the powder in. Once settled things should even out a bit more if the powder is the culprit.

WINNER! Bet the tip is contacting the inside of the seating stem before the ogive is.

Blacken (sharpie) a bullet from the tip past the ogive. Let drive. Seat bullet.....report back.

If any of the ink is wiped off the tip, you have found the source of the inconsistency.

 

[Tempus Tom]

Lee's Dead Length Bullet Seater is said to help with seating OAL. The bottom of the seat die contacts the shell holder. It acts as a stop & should remove any slop from the press? Comes as a set with the Collet Neck Sizer.

I love the Lee dead length seater. I find it a really useful tool for achieving more consistent COAL.