My youngest son is doing his first Buffalo hunt next month with me in Moz. He likes my Win 70 Safari in .375 H&H, so I found him a new one in Florida and bought it. Pretty much the same as my 20 year old rifle except for much nicer wood. We started working up loads for him with Barnes 270 gr TSX and Banded Solids (old flat nose).
I have a load that shoots very well in my rifle, so we started 2 grains below my load and found that with 2 grains less powder (RL 15), his rifle shoots any 74 fps faster! My averages 2710 and his averages 2787 with less powder. Good accuracy, too. I’ve read many times about “fast” rifles but this is the first time I’ve seen it myself.

Are you comparing loads using the same lot of powder?

RL-15 can vary from lot to lot.

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Are you comparing loads using the same lot of powder? RL-15 can vary from lot to lot.

Yep, same 5 lb jug, same lot. Maybe my 20 year old rifle’s rifling might be worn a bit?

Slug the bores and compare both dia. and smoothness.

Bet there's a difference.

George

I have an opinion as to different speeds with same load in different barrels. My family shoots four different rifles in .270 WSM chamberings. All are Model 70 Winchesters deluxe feather weights. One is stainless steel barrel the others blue. The stainless barrel is an all weather model and it shoots all loads 50 plus fps faster than the other barrels. Also the brass shot through the stainless barrel has difficulty with brass shot through the other barrels and resized to shoot again. We also shoot two Custom .358 STA's. One from the Winchester Custom Shop and a stainless barrel. The other a custom built with a Lilja stainless barrel also a Model 70 Winchester post 64 action. The Lilja barrel will shoot all identical loads 50 to 100 fps faster than the Custom Shop rifle. Also brass shot with Winchester custom shop rifle will not chamber in the Lilja barrel after resizing. My conclusion is the chamber differences are the reason for the different speeds of loads. You be the judge. Good Shooting.

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Originally posted by K Evans:

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Are you comparing loads using the same lot of powder? RL-15 can vary from lot to lot.

Yep, same 5 lb jug, same lot. Maybe my 20 year old rifle’s rifling might be worn a bit?

Thats a very real possibility. How much use has it seen over those 20 years?

Two rifles two barrels.

I have tested 5 brand new Mannlicher Luxus rifles.

All exactly the same, with Norma 150 grain soft points.

They were all 270 Winchester.

Difference in velocity was over 150 gps between the fasted and the slowest.

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Thats a very real possibility. How much use has it seen over those 20 years?

I have shot this rifle a pretty good bit over the years, don’t know how many rounds thru it, but I have at least 300 cases, all fired at least once. However, a lot of the loads have not been loaded very hot. I think Saeed’s test of the five new rifles shows that each rifle is the same but different. Maybe manufacturing tolerances during boring and rifling?

Such velocity variations between rifles are not uncommon.

However, velocity is almost always a function of pressure, so backing off by the two grains is a good idea. That load may still be producing more pressure in the new rifle than the +2 grain load in the older rifle. Watch for pressure signs, which may or may not be present with the newer rifle.

I have a Sako .270 which chronographs about 100 fps higher than book with a 130 grain bullet, but uses 1.5 grains less of 4831 to do it. If I were to boost it up to the usual load of 4831 that most .270's digest bolt lift would be stiff and primers would start to crater.

I had two identical Kreiger barrels made at the same time. The same gunsmith chambered these, one after the other. When the second barrel was finally installed (by that same gunsmith) it shot the exact same load as the first barrel but over 100 fps faster.

Very common; ignore it. Forget about the velocities; practice is far more important. Field positions not bench.
Your son is super lucky; I wanted to kill a Cape buffalo since age 8; never got to do it. Too late now. I even have 9 double rifles for the job.

If you shoot enough different rifles, you would know that sometimes crazy things happen that cannot be logically explained!

I have had factory rifles which would not digest factory ammo, or minimum loads.

An example was a BRNO in 243 Winchester!

I am talking many years ago.

Factory ammo blow the primers.

We slugged it, and found the barrel very tight.

I think it was .239 or so.

Other rifles would digest loads that are several grains above book maximum without any trouble.

Point is test your rifle.

And strive for accuracy rather than more velocity.

Some rifles shoot better with starting loads.

Others prefer more powder.

I had the Garmin at the indoor pistol range this week and found my most accurate reload, 10 shots into just over an inch @20 yards, had a velocity spread of 112 fps over the ten shots, from 989' to 1101'. Usually the loads with the lowest spreads produce the best accuracy, but this one defied the norm.

I think they are talking about velocities varying from rifle to rifle. Variations wittin one rifle and one load, is far more consequential in a rifle than in a slow pistol cartridge.
Your loads prove that.

I built a 22-243, shoots 1/4” inch groups.

But the velocity variation between shots can be about 150 gps!!!???

Never understood that!

I get the same thing with my Savage 110's in .223 Rem. All loads the same but sometimes the spread in velocity is 100-150 fps. But the result on the target is all in the same ragged 1/4 inch hole. Same brass, primers, powder, bullets. If you shoot enough you will see funny things. One thing is sure each barrel has a personality all it's own and will tell you about it if you shoot enough. Good Shooting.

It is what it is, but usually works, the bottom line is where the holes in the target land.