question on cold/clean bore velocity readings

[bteate]

I've got some 165gr AB 300WSM ammo from a place called Independence Ammo that came with a rifle that I traded for. The label states velocity @ 3180fps, which I thought was a little high, but most labels are.The rifle is a Savage model 12 with 26" barrel. Today, I recieved the replacement stock from Choate and fired a few rounds from a sqeeky clean bore w/ temp. @ 85*

1-3051
2-3093
3-3197
4-3189
5-3220
6-3182

Is my chrono going out, or is this something usual for some rifles. I've never had one to be that extreme. No pressure signs, no sticky bolt or anything. Any thoughts?
I know that its hard to determine without knowing charge, type powder, etc. but I'd like to be ready for this when I start reloading, or is it a fluke thing.

 

[DrMike]

You velocities are not out of the usual for a 165 grain AB. The velocity is pretty close to what is advertised, though the standard deviation is somewhat extreme. Is this ammunition they loaded? Or is this a common ammunition that they are remarketing? FWIW, some commercial ammunition has exceptionally large SDs, though generally the manufacturers today are marketing some very good stuff.

 

[Desert Fox]

There's nothing unusual with your chronograph reading. The first two was slow due to clean bore. My 7WSM is the same way. The fouling shot is always a tad slower than the rest.

 

[Oldtrader3]

+1 on the standard deviation issues which Dr. Mike observed.

The observed velocity range is pretty high, even for a dry, clean barrel. How does the ammo group at 100 yards, or better still, 200 yards?

 

[SJB358]

I see the same things through a clean and "lightly" oiled bore as well. Seems like if you take out the first two shots, the rest all in okay.

Like Charlie said, how did it shoot? Scotty

 

[bteate]

the rifle has had 72 rounds through it when I got it, and the bore was dirty, not all that bad , but was not super clean. Before I took the stock off, I shot the same ammo into a .630" 3-shot group at 100 ( did not have the chrono set up). While the stock was gone ,I took the time to give it a good cleaning (not too many patches to get it clean either).

Grouping yesterday @100 was about 1.5".

Next question, how do I go about working up loads? foul-up the barrel and keep it somewhat dirty, or try to find a good clean bore load? and is that even possible?

 

[HeathSexton]

I always work with a fouled bore. If my rifles are clean I will fire 2 foulers, let them cool off for about 10-15mins and then work on loads. I always hunt with a dirty bore so I do load work the same.

 

[bteate]

Is this ammunition they loaded? Or is this a common ammunition that they are remarketing?

DrMike, I had the name wrong, its Independent Ammo, LLC. I hav'nt contacted them, but I assume that it is ammo that they load.

 

[Guy Miner]

Shots 3 - 6 are reasonably consistent, although you'll handily beat that by hand loading.

Shots 1 & 2 are likely slower due to the clean bore. Not unusual.

Very representative 165 gr velocity, somewhere around 3100 fps is what I'd expect. It's a good cartridge.