Bought a better caliper and re-measured everything again. Opened three o them up so far and I will attempt to sleuth this round.... don't spoil it if you already have the FGMB recipe, just doing it for fun. OAL still not consistent, and you will notice the powder length are inconsistent as well. Using Neiko Calipers, hornady 5-26 comparator insert, and the 375 head space insert. Will update as I go along.

I picked up a few different ammos to try out and the Federal gold medal berger OAL was just as bad as hornady black. I will re-measure all of the ammo in the coming days to reverify this statement Update: Yes, it has ever so slightly better COAL, worse CBTO I have already tried a few different ammos from a fixture and American eagle 140 OTM performed the best so far (did not have FGMB at the time). Picked up a few more ammos to shoot from the shoulder and see what I get. I suppose I will update this as I go along, will probably open a round or two of some of these for the sake of science.








American eagle results from fixture



Cracked open three rounds, will do another two at a later date, will get MV with a magneetospeed and run some numbers in quickload to figure out the powder... Which I am sure someone can just call by sight, but please don't spoil it. for me





The powder grains measure .035-.0355" diameter and are anywhere from .1135 to .04 in length. picture will come here in a minute.

For the sake of science I hope you aren't wasting your time measuring base to meplat.

I will be breaking out the comparator later today to measure CBTO, but surely inconsistent OAL will have an effect... somewhere

But how does it shoot?

I don't even pay attention to OAL unless there is a feeding issue. Base to ogive is all I care about.

Yes if the bullet length is different(bullet base to meplat) from one to the next on a hollow point boat tail, that could indicate that the meplats are of different diameters which will effect BC a small amount.

For the bullets I don't trim and point I sort and group by length (after confirming the bullet base to to ogive is the same).


No need to be concerned with it for under 400yds probably though.

A 3% difference in BC at 400yds with my 140hyb Grendel load is 0.4" of vertical difference.

We will find out soon I suppose.

What takes more time, sorting by BTO/length or trimming/pointing?

Sorting alone takes longer because there is more scrutiny and you are putting them into groups.
I only use Bergers for LR and have found their base to ogive is very consistent for the most part. I only check about 50 or so of them bto(same lot) unless I find them all over the place (more than +/-.001). Then go through and measure length.
Of course this is all done from the couch while watching a movie or whatever so the time doesn't really count.

I can trim and point 100 in about 10-15 minutes. (Giraud trimmer).
When trimming and pointing I grab a bunch and take 5 minutes to check bto and look for the average length and the shorter ones to setup the trimmer.   

Here a vid of doing it. I think these are 175smks but I don't bother with those anymore as I only use them for 100-200yds.

 

I may need to get another set of calipers due to small variances, but the shortest round was more than likely a typo... will post up new numbers when I get home. CBTO was pretty good, but OAL was still not as good as some other ammo.

Remeasured all the FGMB. I also numbered them so I can go back to a specific round if need be. Will do other bullets after get my homework done. I used a hornady gauge with the 4-25 insert.

I never use factory ammo to know what to expect but that seem alright. My handloads I keep BTO to +/-.0005" but that is with .001" neck tension.

Start adding more neck tension and less uniform brass and you will have to put up with more variance...  or seat shallow, measure, sort, seat again, measure, sort, seat again.

And again hollow points are going to be different  lengths at the meplat from drawing the jackets, just the way it is. 

I would have to say that the AE rounds have the most un-uniform meplats out of all of them, but shoot the best so far out to 300.

What setup do you use? forster press and dies?

Most(almost all) of my precision ammo is loaded on my Hornady Classic press. I use Forster Ultra(.308 6.5G) and Redding Competition(.223) seating dies. Foster Bushing bump die(.308 .223) and Redding type S FL(6.5G) sizing dies.

I use Lapua brass only because of the consistent neck wall thickness across all the cases and around the circumference of each. I don't like Hornady brass, the wall thickness varies too much.

what do you prefer for the seating, forster or the redding?

They both work the same but I like the Forsters better,  I bought the Redding for .223 because Forsters were out of stock everywhere.

They both make straight ammo, as far as results, I don't see a difference.
I prefer the bigger, easier to read knob of the Forster, the Forster feels a bit smoother. Forster is less expensive.

Remeasured with new calipers. OP edited to reflect.

Just got back from the range.

TL;DR FGMB ain't so great.

On the other hand, it is smoking hot at 2905fps average from a 26" barrel. So if it shoots well from your gun, have at it.

I'm sure there is more to it, but there is almost a direct correlation between COAL and rounds that did not perform well in my rifle; could very well be coincidence, though.

FGMB seems to have inconsistent COAL, inconsistent CBTO, inconsistent charge weight. Is the projectile the only thing good about it? Or does my rifle just not like it?

That's impossible!! Tibosaurusrex put 3 in the same hole with that ammo. Kidding of course, as I have a lot of doubts about that video.

Are you sure that one round recorded as being .005 longer is accurate? Outside of that 1, the rest looked like they were within 2 thou of each other (BTO), which shouldn't cause an issue. I think that what you're seeing is that your rifle just doesn't like that bullet at the factory speed or seating depth. All of the other rounds tested are several thou closer to the lands.

I measured the highs and lows three times to verify.