Unaccetable varianace in COAL with Berger VLDs?

[JayR]

When I went to work up a new load for a .260AI with the 130 Berger VLDs, my COALs were all over the place. I typically measure the chamber to get the COAL and then set my first round for about .005" jump, take that round and measure base to ogive and go off that, and measure every 5 rounds or so confirm a constant measurement. When I did that today, I had cases with as much as .015" difference. I know each bullet from the ogive to the tip will be inconsistent, but I have never experienced that much variation from round to round. I typically like less than .003" variance, is that about right? Could it be that I was loading VLDs with a regular seating stem? I load Bergers in other cartridges and love them, but I also have the VLD stem in those. Thanks for the input.

 

[Mikecr]

All we could do is guess and there can be many causes.
Sounds like you have a lot of investigating to do.

Your cartridge base to ogive(CBTO) should not vary ~3thou. I would stop reloading and fix this.
You should measure every one and every one should measure the same. Then load ammo.
Do you have a bullet puller?

 

[cowboy]

Is there any chance you are using a compressed powder charge?

 

[Broz]

I want to make sure I have this right.

Are you getting the inconsistent reading using a bullet comparator from case head to O-give?

Or the OAL from case head to bullet tip?

Jeff

 

[Wachsmann]

I get some degree of variance but I don't use a VLD seater stem. I'm shooting a 6.5x284 and a 300 rum. I usually get about .005 to .008 at the most in OAL. I've been thinking about drilling the stem out so the bullet will seat on the ogive instead of the nose. I went shooting the other day and I had some that repeated velocities and some the would be 10 to 14 FPS off. I was load testing in groups of 3 shots. This made me wonder if the seating could be causing this but who knows. Also I did not clean between the 3 shots so it could be a number of things. Even with this degree of variance my 6.5 shoots .5moa. So I have not been to apt to mess with it.

 

[MNbogboy]

As Mikecr said your CBTO should not be varying much...The COAL you are measuring is normal for Bergers as of late....but the base to ogive should be fairly consistent in spite of the huge variances in actual bullet length...The distance to the lands will remain very close regardless of the COAL... And yes .015 length difference is not an uncommon within the same bullet lot...My guess is that your "jump" is probably fairly consistent and that your COALS are normal for your "lot" of bullets...Your seating stem is probably OK for your Bergers unless some meplats are actually hitting the tip....Other concerns as mentioned earlier are compressed loading and seating pressures and seating technique that all affect COAL and CBTO..

However Bergers as of late are very different animals when there is a lot change...So if you can afford to buy a 1000 or more at a time you could be better off....I have seen .015 off in CBTO with a lot change and .050 thou in length...I can't afford to be buying 1000 at a time and can't afford to burn out any more barrels working up a new load every time I get a new "lot" of the same bullet...So for that reason my plan is not to buy any more Bergers until they learn to change dies more frequently...There are other bullets out there that remain way more consistent from lot to lot.....

Good Luck,
Randy

 

[JayR]

Thank you all for your input. To be clear, I started with my Sinclair seating depth gauge, I took that measurement and made my first round and then measured the case head to ogive. I set my seater die with a regular stem, made my second round, it was within .002" of the first, so I made 5 more and checked the 6th, it was.015" off base to ogive and also COAL. I went back and checked each round and set each one at a time, with having to pull some. It is a slightly compressed load, but I was thinking the problem might be a combination of bullet inconsistencies and and the regular stem hitting above the ogive.

 

[Broz]

If you get a variance between rounds from case head to Ogive using a bullet comparator I don't see how it could be the bullet?

Could be the compressed load and not enough neck tension to hold them?

Could be the seating die plug bottoming out on the tip?

Could be the method of seating or faster strokes on some?

Jeff

 

[Coach Hunt]

Howdy,

Had the same problem on Bergers in a .280 Remington. Finally found the problem by taking the die apart, and putting the seating stem on a bullet so I could check the contact. It wasn't deep enough and the long nose of the bullet "bottomed out" in the seating stem. Drilled it out, smoothed it with emery cloth and problem solved. Just a guess of course, but try it.

Good shooting.

Coach

 

[cowboy]

It is a slightly compressed load, but I was thinking the problem might be a combination of bullet inconsistencies and and the regular stem hitting above the ogive.

It sure could be bullet inconsistancies or stem problems but I would try the following first.

IMHO on "any" compressed load you have to take extra precautions with "any" bullet to maintain consistant base to ojive dimensions.

A couple of things you might try:
- Use an extented tube on your powder funnel
- If you do not have an extended tube you can fill your brass with powder, then take brass with powder in it and tap "lightly" on your reloading table.

The purpose of both above suggestions is to allow the kernels of powder to align themselves within the brass rather than just stacking one on top of the other.

Another thing you can do is seat your bullet 1/3 the way down, lift your ram slightly and rotate your brass 120 degrees, push ram down to seat to 2/3 way home, lift ram rotate brass final seat, lift ram and repeat final stroke 2-3 times.

Keep in mind - and I do not know your bullet seating procedure - but if you just seat a bullet on a compressed charge with one stroke you will be smashing or crushing kernels of powder and it will not be consistant oal more than likely.

 

[MNbogboy]

+1 on all of the above posts...Looks like everybody has run into the same problems at one time or another....Drilling out the top of the stem won't hurt even if you don't think it is a problem (mine are all drilled out in the three calibers that I shoot VLDs with and two of them were hitting)....Very light neck tension and compressed loads will give you fits....worse yet varying neck tension...I use a version very similar to Cowboy's seating method and it will show up as more consistent....Consistency is the key word here....

I'm sorry that I jumped to conclusions on your first post by thinking just your COAL was off...With bergers COAL means nothing...but getting the CBTO close is what we all are "shooting" for (pun intended)...

Good luck,
Randy

 

[65WSM]

Why are you not using a Wilson seating die (they are made for VLD bullets). I load both the .300 RUM and 6.5-284 (along with 3 other more obscure 6.5 wildcats). The Wilson seating die that is reamed with your chamber when your rifle is barreled is the best seating die you can get. Off the shelf Wilsons are available in both cartriges and are much superior to threaded dies when you compare ogive length and runout.

Wilson seating dies cost just over $50.

 

[HunterGreen]

As Mikecr said your CBTO should not be varying much...The COAL you are measuring is normal for Bergers as of late....but the base to ogive should be fairly consistent in spite of the huge variances in actual bullet length...The distance to the lands will remain very close regardless of the COAL... And yes .015 length difference is not an uncommon within the same bullet lot...My guess is that your "jump" is probably fairly consistent and that your COALS are normal for your "lot" of bullets...Your seating stem is probably OK for your Bergers unless some meplats are actually hitting the tip....Other concerns as mentioned earlier are compressed loading and seating pressures and seating technique that all affect COAL and CBTO..

However Bergers as of late are very different animals when there is a lot change...So if you can afford to buy a 1000 or more at a time you could be better off....I have seen .015 off in CBTO with a lot change and .050 thou in length...I can't afford to be buying 1000 at a time and can't afford to burn out any more barrels working up a new load every time I get a new "lot" of the same bullet...So for that reason my plan is not to buy any more Bergers until they learn to change dies more frequently...There are other bullets out there that remain way more consistent from lot to lot.....

Good Luck,
Randy

Very interesting, I just bought 3 boxes of 6mm berger and when measured length they all were way way off..

 

[Mikecr]

They don't make bullets like we make ammo(to a blueprint). They make them however they turn out but consistent in lot.
It's the same with barrels, and I have no idea why we accept this.