GMX searing depth

Heym SR20

Well-Known Member
#1
What is the correct seating depth. I like to crimp into the cannelure, but on these you have two groves. With the top one it seems the bullet is seated very deep in the case. Advise please. I am using the 139g Hornady GMX.
 

Tom D

Well-Known Member
#2
You want the best concentricity, so if the ogive is inside the neck thats not good likewise the base or boat tail should be below the bottom of the neck, then you also need to think about freebore. Changing depth will alter pressure too. If neither grove matches up you could just crimp where it suits.
 

baguio

Well-Known Member
#5
S.A.A.M.I Spec for 7mm-08 and 284 Winchester overall cartridge length is 2.800". You should consider getting a manual though!
Baguio
 

Heym SR20

Well-Known Member
#8
I am looking at both 7x57 and 7x65R. For the 7x57 its perfect for 3.00" OAL if seated at the top cannelure, but in the 7x65 I am currently using the flat base Horady softpoint seated in the cannelure, but the GMX looks to be seated deeper. I am quite keen to keep to same seating depth so don't have to faff with adjusting things each time.

I use IMR4831 - 51.5g in the 7x65R

Haven't started working up a 7x57 load but erring on the side of IMR4350
 

Alantoo

Well-Known Member
#9
I am looking at both 7x57 and 7x65R. For the 7x57 its perfect for 3.00" OAL if seated at the top cannelure, but in the 7x65 I am currently using the flat base Horady softpoint seated in the cannelure, but the GMX looks to be seated deeper. I am quite keen to keep to same seating depth so don't have to faff with adjusting things each time.

I use IMR4831 - 51.5g in the 7x65R

Haven't started working up a 7x57 load but erring on the side of IMR4350
PM sent

Alan
 

Muir

Well-Known Member
#10
I am quite keen to keep to same seating depth so don't have to faff with adjusting things each time.
Seriously??!!??? It's too much of a chore to adjust a seating depth for a different bullet?? Did someone set up you dies for you when you started reloading? ;)~Muir
 

Ray7756

Well-Known Member
#14
Its not difficult to check seating depth / oal when loading , i check every 5 rounds as one of the dies i use is the Lee which does not have a locking system, also dirt lube etc can build up on seating dies and can affect seating depth / oal, if you are just "churning them out " you will have inconsistancies if you take your time you will have accuracy
i use the Lyman " Lock n Load" quarter turn on all my dies so it is easy to change calibre, but i still check seating depth / oal , its attention to detail that gets accuracy
Cheers
Ray
 

brunel-999

Well-Known Member
#15
What is the correct seating depth. I like to crimp into the cannelure, but on these you have two groves. With the top one it seems the bullet is seated very deep in the case. Advise please. I am using the 139g Hornady GMX.
As other posters have said, the OAL of your rifle is the most important consideration. I always set the depth of the seating to suit my rifle OAL (minus gap) and the crimp comes where it comes - irrespective of where the cannelure is. On my 6.5mm x 55 Mauser M03, the correct bullet seating results in the cannelure above the top of the case.
 

Muir

Well-Known Member
#16
Muir you sound like an old woman ,leave him alone Heyme that is.
I am an old woman. But I've been a reloader for many decades, and have taught reloading professionally. If someone has such a problem adjusting the seating stem on their dies to the extent that they want to load all their bullets with the same setting, then maybe they are doing something that causes it to be more difficult for them than it should be. Maybe I could show him a couple of ways to change bullets, and then back with good accuracy -other than the obvious method of progressively seating the bullet deeper until you get the OAL you want.

There are a lot of good reloaders on this site, and there are the ones who want to handload without learning to handload. If you've read my posts I'm sure they seem, at times, abrasive. I especially bridle when someone comes on the site asking for a load for X bullet with Y powder: often when the extreme spread between min and max is 3 grains. But that doesn't matter. With very few exceptions, there is no one load. I tell them to 'do the work' or in otherwords, quit being so timid and/or lazy and get started. Developing loads is part of the handloading discipline, and far too may people are willing to give a newbie their "pet load" instead of a link to the maker and the advice to start at minimum and work up. I think a goodly chunk of the people on this site don't own a manual or refuse to read it because they come asking questions that are covered in any book on reloading. Just as die set up is covered and should be second nature to all reloaders.

You seem pretty willing to let HeymSR20 slide instead of helping him get past this unnecessary dilemma he is facing. I might be an old woman but maybe you don't give a damn? ~Muir
 

Southern

Well-Known Member
#17
Heym, you are going to "have to faff with adjusting the seating depth" because the ogives are different among the various 139-gr Hornady bullets. Hornady lists the COAL at 3.00 inches for the GMX and all the other bullets, which means a longer, sleeker bullet will be seated deeper, and have more lede ( jump to the lands ), as the GMX should. Hornady also lists the same powder loads and velocities for all the bullets, which surely is not true with the GMX.
"
 

JohnT

Well-Known Member
#19
Muir +1:thumb:

To my mind, you reload either to save money (questionable/dependent on how many rounds you go through) or to fine-tune your ammunition to your rifle for accuracy.
I am in no way anywhere near Muir's league, but I have reloaded for many calibres, both rifle and pistol, over the last quarter of a century. Safety is the overriding watchword and is assured by operators following well tried and tested methods in developing their loads. Leaving a seating die set for different loads is not, in my opinion, safe nor is it sensible considering what the operator is trying to achieve. Why bother reloading if you are not giving yourself every opportunity to succeed?
I can understand anyone new to reloading wanting to limit the number of things that they change, but unless they treat each round as a unique product they will never learn or progress.
Follow Muir's advice and progress.
 

bewsher500

Well-Known Member
#20
God trial by SD
answer the question instead of assassinating the technique
Work up a suitably accurate load with the oal set to at least one calibre depth of shank in the neck
avoid leaving a gap at the edge of the neck I.e. Seat neck edge on a driving band or at junction of shank and ogive

Chances are the accuracy will be fine seated at the current oal anyway

my 53gr hollow point, secant ogive copper .224 loads are seated to the same oal as my 60gr soft point Spitzer bullets

They shoot to within 1/2" of each other. No need to adjust
 

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