Chrono Results

[orion]

Here is an interesting one.

I went to the range last Saturday and shot a few loads through the chrony. It was a nice sunny day about 45 or 50 and shot my 22 rim through the machine to check for calibration which checked out ok.

I then shot several loads all using pre measured bottles with 63 grains of Reloader 7, which was my hunting load last fall.

Results:

300 grain .458 Hornaday Hollow Point and Harvester crush rib Ave. = 2159 FPs

300 grain Barnes MZ Expander Supplied Sabot, Ave. 2205 FPS

Now the intersting one :

350 grain .458 Speer Soft Point, Harvester Crush Rib, Ave. 2190 FPS


I only shot about 5 shots each, but the results seemed consistent as the variation in each string was very good within + or - 20 fps
I expected a much lower velocity with 350 grain. Anyone else experiance this?

Thoughts?

[fowlplay]

Orion,
The 350 grain bullet has more weight for a more complete burn of the powder.

When I was shooting RL-7 I was actually getting faster speed out of the 300 grain bullets compared to the 250 grain with the same amount of powder.

A tight fitting MMP sabot on the Barnes would be my guess why the Expander was faster.
Steve

[rbinar]

Mar 17, 2009 9:50:27 GMT -5 orion said:

Now the interesting one :

350 grain .458 Speer Soft Point, Harvester Crush Rib, Ave. 2190 FPS


I only shot about 5 shots each, but the results seemed consistent as the variation in each string was very good within + or - 20 fps
I expected a much lower velocity with 350 grain. Anyone else experiance this?

Thoughts?

I wrote this in a recent post:
"H4198 with shoot the 363 grain bullet (count the sabot weight) as fast as a 313 (sabot again) grain bullet with the same amount of powder. Why? Because the extra weight of the bullet and fairly fast powder provide relative efficiency. Loads of 65 to 68 grains operate below but near sabot disruption. That means you are getting the most bullet energy with the least recoil possible for this amount of powder."

When you get to the 350 grain level you have finally reached enough inertial resistance where the loads start to act normally. I've long stated that the problem with a 50 caliber rifle and slower burning powder is the lack of pressure.

I've often wondered why shooters who prefer a relatively slow bullet in .458 don't switch to the 350 grain bullet. There is more recoil but to those who don't mind that the bullet is much better down range and loads can be very consistent with very low SDs.

[orion]

I will probably try these bullets for accuracy some time in the near future and report back, the recoil did not seem too horrendous at that level but was definatley starting to become noticable. It seems the bullet length and profile would provide a better ballistic coeficient than the various 300 grain hollow points, and would obviously carry more energy at the longer ranges.

I have seen that Big Moose has/is using the 350 Barnes but I am not sure what the nose profile is on that bullet?

Regards