ATF APPROVED!!! 4/29/05
The 550 Express was designed to be the most powerful round one could legitimately fit into a
sporting/hunting Mauser. It is designed to throw a 700gr bullets 2124fps, and exceed 7000 ft-lbs. It does
this and more, and has tolerable recoil. In short, it beats the 577 Nitro!! (approaching 2200fps with 700gr)
FINALLY- i got to finish this beast and actually light the fires!!!
Quickload can NOT handle big straight rounds. At no point did a load and pressure/vel sync up..
Some preliminary 550 Express data!!
(these loads appeared safe in my particular gun, yours WILL vary. Do NOT take this as loading data.
This is for INFORMATIONAL use only)
23" barrel bausa barrel (my custom profile)
Weatherby 416 brass, 2.65"
Single stack mag 3 down, 1 up
boyds lam JRS stock
necg front sight
intregal rear island sight (cz take off 1 up, 2 down)
intregal barrel lug under sights
brass cup holding in barrel lug
ruger/brownells barrel sling mount
blc2 (pretty dull)
665 gr casts 3.2 oal
93gr 1783 4695 ft-lbs
100gr 1980 5790 ft-lbs
70gr hawks 3.325 oal
96gr 1796 5015 ft-lbs
665 gr casts (3.2 oal)
h335 (much better)
92 gr 2037 6129 ft-lbs
94gr 2120 6638 ft-lbs
96gr 2141 6770 ft-lbs
98gr 2159 6885 ft-lbs
100gr 2184 7045 ft-lbs (YES- round PROVEN)
102gr 2219 7273 ft-lbs
104gr 2234 7371 ft-lbs
106gr 2263 7564 ft-lbs
108gr 2295 7779 ft-lbs
110gr 2321 7957 ft-lbs
that's right, 8000 ft-lbs from a MAUSER vz 24 action
700gr hawks 3.325 oal
102gr 2109 6915 ft-lbs
106gr 2115 6955 ft-lbs
108gr 2144 7147 ft-lbs (MORE than a 577 nitro)
110gr 2169 7314 ft-lbs
700gr hawk, 3.25 oal
105gr 2131 7060 ft-lbs (and i think this is THE load)
110 gr 2193 7477 ft-lbs
Cases stayed "smoked neck" until around 104-105 grains, neck wrinkle didn't go away until 108 gr.
Man, my shoulder is a little tired!!! Accuracy trailed off at the end.. i think that was mostly me being punchy!!
Anyway, the primers all looked VERY reasonable... Until the ~105gr loads, I think it was low 40s kpsi. The 110
grain loads, both 3.325 and 3.25 looked about like a normal reloaded 30-06... I think that 105 should be
considered THE load. If you want more, go for it, but 7000ft/lbs and a 700gr bullet... SD of .331, gun weight,
about 11.5, recoil, about 110 ft-lbs.
And yes, the chrony survived all this!!!
If you are working on an express, 90 grains should be a reasonable starting point.
So, at this point, *I* had about a net 50 yard 10", shooting offhand, with all these loads... When i marked
several of them, it seemed to be more like a series of 3-4" groups... At 25 yards, well, it's a bunch smaller.
Feeding was "okay" for everything but the last round.. But, hey, I've already taken that mag box out and I am
working on V2.. As I can SEE what's wrong with it.