02-16-2020, 07:54 PM
(This post was last modified: 02-17-2020, 02:42 PM by lazyengineer.)
To follow-up, I used a Hornady OAL measurement tool to measure the chamber OAL to the lands, with every Grendel bullet I have. Very interesting results. The throat is not too long, and if anything, is actually rather short. Indeed, some of my loads likely were longer than the throat, though not all. At 200 rounds, which I consider about the proper round count to measure throat AOL (new barrels sometimes don't measure right), I got the following table - in order of bullet wt:
OAL to tip - Bullet for 20" Monster BBL @ 200 rounds of erosion.
[COLOR="#008000"]2.235" - 90gr Speer TNT (spitzer)
2.208" - 95gr H. V-Max (tipped BT)
2.135" - 100gr H. ELD-M (tipped BT)
2.220" - 100gr H. AMAX (tipped BT)
2.242" - 100gr Nos. Monster Match (Nosler Custom Competition, HPBT)
2.220" - 120gr H. ELD-M (tipped BT)
[/COLOR]2.312" - 120gr Speer Gold Dot (bonded semi-BT)
2.235" - 120 SMK (HPBT)
2.230" - 123gr Nos. CC (HPBT)
--- - 123gr H. SST
--- - 123gr H. ELD
--- - 123gr H. HPBT (don't have the above bullets loose in inventory)
2.220" - 129gr H. Interbond SP (lead tipped Spitzer)
[COLOR="#FF0000"]2.313" - 129gr H. SST (tipped BT)
2.370" - 129gr Nos. AccuBond (Tipped BT)
2.350" - 130gr Nos. RDF (HPBT)[/COLOR]
Note that measurements with this tool are not always precise and can be prone to error, and can easily be +/- 0.010" or more.
Where Green means the bullet OAL is SHORTER than magazine length (2.250"), before hitting the lands
and Red means the bullet AOL is LONGER than magazine length, before hitting the lands.
Which is to say Green means you aren't forced to an accuracy straining long bullet jump to reload, but there is potential for accuracy and safety issues if load them to magazine length.
And Red means can't really index a load off the lands and so subject to bullet jump, but magazine fed rounds can't be loaded so long they will be forced into the lands.
For my next batch, I will match my reloads to be at least 0.010" below this, and yet no more than 0.030", if I can. Some of these I've been running too long.
OAL to tip - Bullet for 20" Monster BBL @ 200 rounds of erosion.
[COLOR="#008000"]2.235" - 90gr Speer TNT (spitzer)
2.208" - 95gr H. V-Max (tipped BT)
2.135" - 100gr H. ELD-M (tipped BT)
2.220" - 100gr H. AMAX (tipped BT)
2.242" - 100gr Nos. Monster Match (Nosler Custom Competition, HPBT)
2.220" - 120gr H. ELD-M (tipped BT)
[/COLOR]2.312" - 120gr Speer Gold Dot (bonded semi-BT)
2.235" - 120 SMK (HPBT)
2.230" - 123gr Nos. CC (HPBT)
--- - 123gr H. SST
--- - 123gr H. ELD
--- - 123gr H. HPBT (don't have the above bullets loose in inventory)
2.220" - 129gr H. Interbond SP (lead tipped Spitzer)
[COLOR="#FF0000"]2.313" - 129gr H. SST (tipped BT)
2.370" - 129gr Nos. AccuBond (Tipped BT)
2.350" - 130gr Nos. RDF (HPBT)[/COLOR]
Note that measurements with this tool are not always precise and can be prone to error, and can easily be +/- 0.010" or more.
Where Green means the bullet OAL is SHORTER than magazine length (2.250"), before hitting the lands
and Red means the bullet AOL is LONGER than magazine length, before hitting the lands.
Which is to say Green means you aren't forced to an accuracy straining long bullet jump to reload, but there is potential for accuracy and safety issues if load them to magazine length.
And Red means can't really index a load off the lands and so subject to bullet jump, but magazine fed rounds can't be loaded so long they will be forced into the lands.
For my next batch, I will match my reloads to be at least 0.010" below this, and yet no more than 0.030", if I can. Some of these I've been running too long.