.025 difference box to box

[XTR]

YMMV, but what I have seen in Bergers is that the variation is usually doesn't change my BTO measurement on loaded rounds at least not significantly so. It would appear that while some of the other demins may vary the distance from where my seater touches the bullet and where my tool measures ogive is consistent.

There are exceptions, particularly with the 90VLD.

 

[Bart B.]

If case head to bullet diameter contact with throat is the dimension to have minimal spread, then case heads must be against bolt faces when the rounds fire.

Are your case heads held against bolt faces hard enough to withstand firing pin impact?

I see no problems if BBTO has several thousandths spread as, when fired and pushed through the bore, bullet bases don't touch anything except powder and gas from burnt powder. Each lot of commercial (Sierra, Berger & equals) match bullets tests about 1/4 MOA avg., 1/2 MOA ES through 200 yards.

 

[powderbrake]

As seen from the Berger response, the bullet base to ogive is closely held.

It is my understanding the ogive to point of the bullet length is not as closely held, as this is the area that all the tolerances accumulate, therefore the touch point of your seating punch will vary a bit, lot to lot.

For a different lot number, I have found that seating the bullet to the same place into the lands will result in essentially the same groups. I do not run at max pressures, so I see no pressure signs. I expect to have to adjust my seater punch with any change in lots.

Always measure CBTO with the SAME adapter on your calipers to repeat the seating depth you need.​

 

[RGRobinett]

Just an FYI. The bullet comparator that I use is one that I made from a left over piece of the original barrel. Cut with the actual reamer used to cut the chamber. So, the comparator is a mirror image of the chamber. Eliminates most variables associated with a generic store bought bullet comparator. Kind of takes us right back to the bullets to my way of thinking. I will seat a few of the new lot, with same setting on the Wilson seater, and see what I come up with.

Paul

Paul, you are a crafty fellow - make a "seater-stem", which is a nice slip-fit in your current comparator, and long enough to contact the bullet nose (about where your "real" stem contacts
the nose) and to protrude out the "muzzle" end, when the bullet is seated against the [comparator] lands. Measure the variation in stem protrusion . . . with bullets from a single die, variation should be scant, while bullet-base, to stem could drive you nutz, or, not! Though I have never had one in hand, I believe this is probably (a variation of) how the Bob Green comparator works.

There can always be "stinkers" - look at what a jacket must survive during point-up - we expect
the jacket material to display some contrary attributes: malleable & ductile, yet springy (well, slightly) . . .blah, blah, blah. That's why I like barrels which deliver the goods via a "jam-seat", as opposed to jumpers.

Please let us know what you observe. RG

 

[MikeMcCasland]

If you think that's bad, I had .035" of difference between lots of their 6.5 130 OTM Hybrids; measured using a Hornady bullet comparator, bullet base to ogive.

I called Berger, and they didn't see anything wrong with it. I posted a thread about it on here in the 6.5 section.

Maybe my expectations were out of alignment.

 

[expiper]

Most folks never have to build//manufacture anything to a blueprint or spec.,,,,,bullets are made from lead/copper that is mined and produced from several mining and manufactureing facilities througout the nation/world,,,,,these metals have various ductility and hardness factors that affect how they respont to extrusion and swedgeing during production process ,,,and bullet dies wear and need replaced occasionally ,,,It is unfathonable how these tool&die makers can reproduce dies with such accuracy,,,then we have the nerve to complain that bullets made in todays die is "different" from those made 5-10 years ago,,,let alone yesterday ,,,that is why there are lot numbers !!!!!!....jacket uniformity and lead with no porosity or anomalys is more important than what can be measured with some gadget that costs $29.95,,,,people should spend more time measuring their targets and learning how to read the wind,,,,Roger

 

[boltfluter]

Paul, you are a crafty fellow - make a "seater-stem", which is a nice slip-fit in your current comparator, and long enough to contact the bullet nose (about where your "real" stem contacts
the nose) and to protrude out the "muzzle" end, when the bullet is seated against the [comparator] lands. Measure the variation in stem protrusion . . . with bullets from a single die, variation should be scant, while bullet-base, to stem could drive you nutz, or, not! Though I have never had one in hand, I believe this is probably (a variation of) how the Bob Green comparator works.

There can always be "stinkers" - look at what a jacket must survive during point-up - we expect
the jacket material to display some contrary attributes: malleable & ductile, yet springy (well, slightly) . . .blah, blah, blah. That's why I like barrels which deliver the goods via a "jam-seat", as opposed to jumpers.

Please let us know what you observe. RG

Randy, thanks for your input. That is a great idea!! We all benefit from your knowledge as a master bullet maker. I will see what I can come up with.

Paul

 

[Riky]

I have seen Sierras that vary up to .039 lot to lot

For that reason i allready eliminated since few years ago Sierra and Lapua as well (both are slopy from base to ogive), but what You state here from Berger left me totaly shocked

 

[avidflyer]

New box of 500 Berger 155 HB
They very .008 high to low any where in between.

Last lot of 185 Berger’s .017 difference.

Maybe there new location is not running to smoothly

Why would you say something like that.....it can’t be true.

 

[Liven The Dream]

Why would you say something like that.....it can’t be true.

Not sure what you are pointing to ?

I took a stab at maybe why the difference ??? Lot to lot machine to machine very ??

 

[4xforfun]

That’s not just a small change either! Could put a guy from .010 to .035 jam... that could suck!!

I'd be curious to know how this works. Your bullet seater doesn't know how long your bullet is. The only thing that will change is that you will have more bullet in the case taking up more powder space. The only thing that would change seating depth is if the bullet Ojive was a different shape.

Now, i'm not taking away the fact that this is a huge difference. My concern on these bullets would be bearing serface ojive to ojive.

Tod

 

[4xforfun]

Just an FYI. The bullet comparator that I use is one that I made from a left over piece of the original barrel. Cut with the actual reamer used to cut the chamber. So, the comparator is a mirror image of the chamber. Eliminates most variables associated with a generic store bought bullet comparator. Kind of takes us right back to the bullets to my way of thinking. I will seat a few of the new lot, with same setting on the Wilson seater, and see what I come up with.

Paul

...untill you take the first shot out of you new chamber and it starts to erode...making the comparator DIFFERENT than your chamber.

Tod

 

[johara1]

You guys are starting to learn they will feed you a line of bull shit. you will need to make them work and just maybe they will but you will start over and you will wear out more barrel life getting them to shoot. The next lot will be different and you will start over again. So now are you you saving anything with factory bullets? ...... I guess it would depend on the level of repeatable accuracy you are looking for..... jim

 

[boltfluter]

...untill you take the first shot out of you new chamber and it starts to erode...making the comparator DIFFERENT than your chamber.

Tod

It will still be much better than just a random sized hole drilled in something. It will also give you a great way to measure your throat erosion, as you have a new chamber in the guage. Try to look on the bright side of things.

Paul

 

[4xforfun]

It will still be much better than just a random sized hole drilled in something. It will also give you a great way to measure your throat erosion, as you have a new chamber in the guage. Try to look on the bright side of things.

Paul

Yep, but what I REALLY like about them is initial bullet setup. I take all of the bullets I plan on trying and get my measurements.

 

[1shot]

Lloyd
These are Sierras 107. So I am almost out of Bullets leading to digging through my stash for an event for this " Weekend "

100 box- BBTO.687 ( half)
100box - BBTO.685 (half)
500 box- BBTO.677 (now empty )
I called a friend his measured
BBTO- .648
.687
- .648
= .039

I ask, because I shoot Sierra 110, 150, 183 bullets. 6mm, 6.5mm, 7mm. I have never found lot to lot variance with those three calibers like you are describing with the 107’s.
Thanks,
Lloyd

 

[avidflyer]

I had some 155’s that were as bad if not worse. Spoke with Phil he said they were in tolerance and to try to shoot a couple. Explained the ogive seating (as above) I was jumping .025 and the new lot did ok but never liked it. Bought a thousand jugs last year from a guy that sorted them .001 lots from +.005 to -.005 and surprisingly not that bad of lot. Sure some runs are better than others and some bullets show more variance then others

 

[Joe Salt]

Guys if your not checking your throat wear once in a while your spinning your wheels.
Your going to have to shoot the short ones and the long ones to see if there is any difference.
And I don't want to hear ! But I'm wearing my barrel out. Boo Ho
I've had Berger's in 30 cal. that were 35 thou. shorter figured they wouldn't shoot. Shot like a house a fire.

Joe Salt

 

[corsair4360]

Would you buy the Berger's if they cost twice the bullet cost that they have in the past? If you really want perfectly consistent bullets, make your own. Bullet manufacturing companies are first and foremost companies to make money satisfying a need in the marketplace.

 

[1shot]

Sometimes we need to remind ourselves that we are in the minority of the bullet makers customers. We are for the most part "A" typical, OCD oriented group of shooters. We stress and worry about the smallest of the small details, and I put myself squarely in the middle of that group.
With that said, if company B or S, isn't making bullets consistent enough for your liking, you can either do as @Joe Salt stated (which I do if the situation warrants it) or pony up and shoot custom bullets.
I hope this helps,

Lloyd