do you ever end up with way less velocity than is published?

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I'm loading my t3 lite 300 win mag with 185 berger classic hunters. I loaded them over 72.6 grains of h4831sc and each was measured on a calibrated gempro 250 my chronograph tells me 2785fps with little spread. Hodgdon lists the starting load for 190s as 69.0 grains producing 2795fps, the max is 73.0 for 2923fps. with a barrel that's 24 3/8" I wouldn't expect to be slower than the published start load with a near mac powder charge.
I also shot some factory 9.3 through a 20 inch barrel and got 2250 so that's about what I was expecting, just the 300 seems off
do you guys find you are way under book values for seemingly no reason.?
 
If you load long enough you're going to see slow barrels and fast, loads that don't make the book at all, and those that surpass it with the starting loads. That's the difference between barrels.

Next you have to realize that there is a lot of difference between manuals. Your velocity seems slow looking at Hodgdons right? Crack open the Nosler book and you're only off 50 fps or so. Go to the Hornady book and they've listed 72 grains for 2800 fps which is about what you're at.

Don't even get me started on different chronographs.

The experienced reloader will learn to cross reference several sources, and also that your gun is going to tell you what it wants and what it it will do with it. It'll tell you when to quit too, but you have to listen to
it.

I've got a 26" barrelled .300 here that likes the 185 gr Classic Hunter; though it doesn't really like anything else. 3050 fps with 73 grains of IMR 4831. Trouble is; that's my barrel and my jug of powder not yours.
 
I concur with Dogleg and other posts like his. YOUR rifle is a law of its own. I'll illustrate.
I have several rifles chambered in 308 Norma Magnum. Two have 26' barrels, and the other
3 have 24" tubes......

Shooting 180 grain Partitions from one lot, and powder from one lot.
One rifle with a custom barrel 24" long, produces 3160 fps with 73 grains of Norma MRP [This is a "fast" barrel]
Another 24" custom barrelled rifle produces 3060 with 75 grains of Norma MRP. [2 grains more powder for 100 fps less velocity]
One of my 26" barrelled rifles produces 3120 with 74.5 grains of IMR7828 [this is about normal]
Eagleye
 
Dogleg said:
Next you have to realize that there is a lot of difference between manuals.

The experienced reloader will learn to cross reference several sources, and also that your gun is going to tell you what it wants and what it it will do with it. It'll tell you when to quit too, but you have to listen to
it.
Click to expand...

The above is the best advice you will hear: listen to it, please.

I have noticed that recently some of the Barnes loads I have been using successfully for some time with amazing accuracy have either been lowered (powder range was 45 grains min to 50 grains max lets say 5 years ago, but now it is 42 grains min to 46 grains max... while my loads are 49grains in this example, at 100% case capacity) or that powder has been removed from their book for that bullet weight and caliber totally. It seems that they have really "toned it down" for some reason while I'm still using that "removed" powder at an "overcharge" with zero over pressure signs and phenomenal accuracy. All the signs, "listening to my gun" and some years of experience tell me so.

Listen to the gun, read the brass and aim for the accuracy / bullet/ results you want.
 
What about air temp and pressure affecting velocity? Not sure if those books post the weather info, but that may be part of it. Certainly at this time of year it's cold out there, and that will slow the bullets down. Not sure how much though.
 
If your Tikka is anything like mine you probably need to add some more powder. With 180 accubonds im using 76gr of H4831sc. (Safe in my my rifle).
 
I used to buy match barrels three at a time. The were consecutively bored, reamed and rifled from the same bar stock on the same machines. they were then chambered with my reamer by the same gunsmith.

Velocity would vary from fast to slow by as much as 150 fps.

If you were to compare velocity between a 24" Winchester and a 24" Remington, I would expect an even bigger difference, with Winchester being the faster.

The manual tells you what THEY got with THEIR rifle. The only significant velocity information is which powders were used to get the higher velocities. That would probably be true of your rifle too. Everything else will be DIFFERENT because they did not use YOUR rifle.

They may have used a pressure barrel, made to SAAMI minimum specs (unlike your rifle) or they may have used a common commercial rifle. Your rifle would almost always develop less velocity than a SAAMI pressure barrel and could be somewhat faster or slower than a commercial rifle.

The manual only gives you approximate or ball park information. It is up to you to develop loads and note your own velocities.
 
I have 2 Winchester model 70's one is Portuguese the other is American. With the same brass, primer, powder charge and bullet one gets 2830fps the other gets 2911fps. Both 22" barrels.
 
Surely there has to be some margin of error? I suppose a chronograph is worth the investment after all. I'm surprised to see an almost 100 FPS difference between two rifles of the same barrel.
 
Dake21 said:
Surely there has to be some margin of error? I suppose a chronograph is worth the investment after all. I'm surprised to see an almost 100 FPS difference between two rifles of the same barrel.
Click to expand...

It's not that unusual to get variations of 100 fps from shot to shot with the same load in the same barrel.

Wait til you get one rifle that comes in a couple hundred slow, and another that pushes an extra couple hundred.
 
If I was getting 100fps extreme spread with a load! I would pull all the bullets in the remaining ones and figure out what went wrong
Anything I load for my goal is single digit extreme spreads. How can a person expect a accuracy if you don't?

I have loaded lots of guns in the same caliber some barrels are fast and some are slow with the same load.
Chronographs are good. Best way to verify it all is to stretch it out a few hundred yards and check your drops.



QUOTE=Dogleg;14481594]It's not that unusual to get variations of 100 fps from shot to shot with the same load in the same barrel.

Wait til you get one rifle that comes in a couple hundred slow, and another that pushes an extra couple hundred.[/QUOTE]
 
Comparing manuals will fry your brain. I've been cross referencing Hornady and Lyman. Some Lyman 150gr 30-06 loads show 4 gr more RL19 than the Hornady does for RL17. IMR4064 very close though.
 
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