50 BMG primer seating depth

[secondofangle2]

Having some trouble with my 50 BMG SDs. Dunno if it's the cold weather, or that fact that I now have a 2250 yard target and a GARMIN measuring shots that makes vertical stringing more obvious, or it is a new problem that sneaked in that I'm not aware of yet.

So as to not turn this into a giant referendum on all things 50 BMG reloading, I wanna focus on one variable: Primer seating depth.

I'm using a ($450!) M2 precision primer seating tool that indexes off the base of the case, not the rim. (RWS brass so almost perfect rim uniformity, but still - there is no better way to seat a primer than M2 in RWS brass). For years I've been using 0.007" seating depth, kinda the same as that guy who will not be named recommends for large rifle.

I no longer have access to FCSA, but a buddy said he saw on there that at least one dude is using 0.0175", which is over double mine, 0.010 more in fact.

Anybody have EXPERIENCE in this domain? Obviously, I'm going to try deeper seating, and I've already changed my setup for 0.015" depth, but I'm wondering how much is too much?

 

[Alan Warner]

Having some trouble with my 50 BMG SDs. Dunno if it's the cold weather, or that fact that I now have a 2250 yard target and a GARMIN measuring shots that makes vertical stringing more obvious, or it is a new problem that sneaked in that I'm not aware of yet.

So as to not turn this into a giant referendum on all things 50 BMG reloading, I wanna focus on one variable: Primer seating depth.

I'm using a ($450!) M2 precision primer seating tool that indexes off the base of the case, not the rim. (RWS brass so almost perfect rim uniformity, but still - there is no better way to seat a primer than M2 in RWS brass). For years I've been using 0.007" seating depth, kinda the same as that guy who will not be named recommends for large rifle.

I no longer have access to FCSA, but a buddy said he saw on there that at least one dude is using 0.0175", which is over double mine, 0.010 more in fact.

Anybody have EXPERIENCE in this domain? Obviously, I'm going to try deeper seating, and I've already changed my setup for 0.015" depth, but I'm wondering how much is too much?

I use an M2 also and set them at .012.
Run a side by side of your .007 and some at .012 and see what the chrono says.
Just an fyi- the newest lot just in is running rim thickness a thou or two larger than what we've all seen for the past four years.
The .675 undercut is now running at .677.
According to Mark C. The new lot is new production where as the older lot was all from stored inventory. Thus the long wait to get the newest shipment.

 

[secondofangle2]

Thanks, Alan

 

[RagnarAW50]

One of the FCSA World Champions wrote up an article years back on seating depth, he did a bunch of experiments and found that .018 yielded the best results for him.

I should have also mentioned the same guy sorts his primers by weight, as far as I know most people do. If you saw how these were made you would be convinced you needed to weigh them if your not already.

 

[secondofangle2]

how do they make them?

 

[A5scott]

Having some trouble with my 50 BMG SDs. Dunno if it's the cold weather, or that fact that I now have a 2250 yard target and a GARMIN measuring shots that makes vertical stringing more obvious, or it is a new problem that sneaked in that I'm not aware of yet.

So as to not turn this into a giant referendum on all things 50 BMG reloading, I wanna focus on one variable: Primer seating depth.

I'm using a ($450!) M2 precision primer seating tool that indexes off the base of the case, not the rim. (RWS brass so almost perfect rim uniformity, but still - there is no better way to seat a primer than M2 in RWS brass). For years I've been using 0.007" seating depth, kinda the same as that guy who will not be named recommends for large rifle.

I no longer have access to FCSA, but a buddy said he saw on there that at least one dude is using 0.0175", which is over double mine, 0.010 more in fact.

Anybody have EXPERIENCE in this domain? Obviously, I'm going to try deeper seating, and I've already changed my setup for 0.015" depth, but I'm wondering how much is too much?

What powder and primer are you using?

Scott

 

[secondofangle2]

RL50 236 grains, 750 AMAX, RWS brass and primer

Previously I was seating them to 0.007. 0.015 made it much better

 

[RagnarAW50]

This is not RWS.....but it shows how the explosive is "buttered" into the primer cups, clearly there is a chance for variation in explosive weight during this process



Good luck! See you at a match I hope!!

 

[secondofangle2]

Yeah, the question is whether the major source of weight variation is the brass or the "butter".

about 10 years ago I was sorting CCI 35 primers before I got my RWS, and I could not tell that it made a difference

 

[Taylorbok]

Yeah, the question is whether the major source of weight variation is the brass or the "butter".

about 10 years ago I was sorting CCI 35 primers before I got my RWS, and I could not tell that it made a difference

IMO it's basically impossible to say, once in a while I'll "sort" primers but for me its more about culling the outliers.