09-27-2024, 02:12 PM
Actual brass length doesn't matter from measuring strictly a COAL dimension, it could affect whether the bullet is seated with enough shank in contact with the neck (which gives seating stability).
But there is a distinct difference between reality vs ideal, and in reloading, reality is king. In reality every brass piece is a different length (which most times is not an issue, since that length may vary +/- 0.001 or 0.002).
Every bullet has a variances both dimensionally within a lot (length/oal, shank length, ogive start, grs weight, etc), as well as differing from lot to lot. So you can't really say that every bullet would hit lands at 2.220 for example... there will always be some variance.
But the biggest variable for seating is the chamber dimensions from barrel to barrel, which can be enough to ruin your day if you are trying to seat some of the more "stubby" of bullets. Example, of my ARCs (both now and prior), some hornady bthp 105's for example, would hit lands at 2.277 down to 2.232 among 4 barrels. The nosler 95 BT would vary to lands from 2.228 down to 2.181, among 4 barrels. This is why you really need to do seating depths for Your Barrel(s), and write them down.
Personally I don't try to chase or seat close to the lands because of all the variables involved, which would also include seating tolerances for your equipment as well as the ones above. (The competitors who do, and "need" to, are typically using an expensive, special order barrel, single powder, and single match grade bullet, and custom expensive reloading equipment... so they reduce all of these variables down to virtually 1 or 2 maybe; so these things they follow are not everyday guidelines for everyday shooters like me)
So bottom line, here are the takeaways I recommend:
1. Size and trim your brass to a consistent length within Saami limits. ARs, full length sizing.
2. Test your bullets in your barrel(s) for oal and choose a length - I say shorter, by 0.020" or up to 0.060-ish depending on the bullet, while still ensuring that bullet has enough shank (min of 1-caliber) inserted/riding against the neck for proper seating - boattail portions don't count for this. Write down these measurements. Each bullet, each barrel. You need an oal comparator like the hornady gage, the hornady modified case+digital calipers, or whatever mfr trips your fancy. You need to be able to distinguish down to the 0.001's for chamber seating-lands, etc., hence the digital calipers.
3. Keep powder loads within mfr recommended limits but always work up from low, for each barrel, each load setup. The eyes/rifle/life you save may be your own. You might not make it up to a mfr listing of max, so be prepared to stop before that... you don't have to shoot it just because you loaded it!!! Too hot is too hot.
4. After you get lots of run time with this caliber, then maybe you can consider using some off-book powder, carefully and working up as above. These grendel-based cartridges don't show hot overloads as commonly-observable or as easily as 308/223-based cartridges. This is a fact of life and you are well to keep it in mind.
Safety is first and foremost in all of this.
But there is a distinct difference between reality vs ideal, and in reloading, reality is king. In reality every brass piece is a different length (which most times is not an issue, since that length may vary +/- 0.001 or 0.002).
Every bullet has a variances both dimensionally within a lot (length/oal, shank length, ogive start, grs weight, etc), as well as differing from lot to lot. So you can't really say that every bullet would hit lands at 2.220 for example... there will always be some variance.
But the biggest variable for seating is the chamber dimensions from barrel to barrel, which can be enough to ruin your day if you are trying to seat some of the more "stubby" of bullets. Example, of my ARCs (both now and prior), some hornady bthp 105's for example, would hit lands at 2.277 down to 2.232 among 4 barrels. The nosler 95 BT would vary to lands from 2.228 down to 2.181, among 4 barrels. This is why you really need to do seating depths for Your Barrel(s), and write them down.
Personally I don't try to chase or seat close to the lands because of all the variables involved, which would also include seating tolerances for your equipment as well as the ones above. (The competitors who do, and "need" to, are typically using an expensive, special order barrel, single powder, and single match grade bullet, and custom expensive reloading equipment... so they reduce all of these variables down to virtually 1 or 2 maybe; so these things they follow are not everyday guidelines for everyday shooters like me)
So bottom line, here are the takeaways I recommend:
1. Size and trim your brass to a consistent length within Saami limits. ARs, full length sizing.
2. Test your bullets in your barrel(s) for oal and choose a length - I say shorter, by 0.020" or up to 0.060-ish depending on the bullet, while still ensuring that bullet has enough shank (min of 1-caliber) inserted/riding against the neck for proper seating - boattail portions don't count for this. Write down these measurements. Each bullet, each barrel. You need an oal comparator like the hornady gage, the hornady modified case+digital calipers, or whatever mfr trips your fancy. You need to be able to distinguish down to the 0.001's for chamber seating-lands, etc., hence the digital calipers.
3. Keep powder loads within mfr recommended limits but always work up from low, for each barrel, each load setup. The eyes/rifle/life you save may be your own. You might not make it up to a mfr listing of max, so be prepared to stop before that... you don't have to shoot it just because you loaded it!!! Too hot is too hot.
4. After you get lots of run time with this caliber, then maybe you can consider using some off-book powder, carefully and working up as above. These grendel-based cartridges don't show hot overloads as commonly-observable or as easily as 308/223-based cartridges. This is a fact of life and you are well to keep it in mind.
Safety is first and foremost in all of this.