Your new barrel may vary from the old in chamber capacity, leade, bore diameter, and smoothness. Once you have worked up a maximum working load, the 26" should give you 50 to 75 fps more velocity, but that is within the variation of two different barrels. You'll simply have to chronograph the two to see.

I'd like to cut a few more barrels and test it out but I dont' think you gain or loose much over 30 fps per inch.

Personally it is not something I would think 2x about.

"GET TO THE HILL"

Dog

I just spent a couple hours at the range today, shooting two 300 Win Mags. One is my Browning A-Bolt Stainless Stalker with a 26" barrel, the other is a buddies Winchester M70 Classic with about a 24" barrel and that darn BOSS thing on the end. The BOSS makes the barrel look about the same length as my A-Bolt, and I'm guessing about the exact length (24") of that barrel.

Anyhow, the first load I tried was my favorite 78.0grs of RL-25 (not RL-22!), 200gr Partitions, Fed 215s, and R-P brass.

In my A-Bolt the chony read (in fps)...

3068
3061
3043
3097
3066

In my friends M70 this load clocked...

2859
2863
2824
2865
2894

That's about 200fps difference between those two rifles.

With a factory load from Federal, with 200gr Sierra Game Kings (hey, a friend gave them to me! ), the difference wasn't so large.

A-Bolt
2726
2756
2809
2732
2717

M70
2823
2795
2789
2797
(no 5th shot)

I'm guessing that the "slow" RL-25 really needs all 26 inches (plus) to really start to work. Not sure what powder blend Federal was using, but it wasn't as responsive to the extra barrel length.

There! Clear as mud, right?

------------------
Brian

Great illustration!

As we all know, no two rifle barrels/chambers are alike, so there can be no precise relationship between the velocities in a 26 vs a 24. (The only accurate test is to cut off a longer barrel and retest it, but it's damn hard to glue the stub back on if it turns out that you really wanted the longer barrel!)

The fact that velocities with RL 25 show a marked improvement with the longer barrel is to be expected, considering how slow the powder is. What's surprising is that the factory loads showed virtually identical velocities. Most factory loads utilize faster powders than handloaders tend to use (less powder, cheaper to produce), so you wouldn't expect as much difference with a factory load, but your results are remarkable.

Just goes to show you that you can never predict performance with any real reliability, and if you want to know what's going on, spend the money-equivalent of a cheap scope and get yourself a chronograph!

quote:

---

Originally posted by BW:
Funny you should ask!

I just spent a couple hours at the range today, shooting two 300 Win Mags. One is my Browning A-Bolt Stainless Stalker with a 26" barrel, the other is a buddies Winchester M70 Classic with about a 24" barrel and that darn BOSS thing on the end. The BOSS makes the barrel look about the same length as my A-Bolt, and I'm guessing about the exact length (24") of that barrel.

Anyhow, the first load I tried was my favorite 78.0grs of RL-25 (not RL-22!), 200gr Partitions, Fed 215s, and R-P brass.

In my A-Bolt the chony read (in fps)...

3068
3061
3043
3097
3066

In my friends M70 this load clocked...

2859
2863
2824
2865
2894

That's about 200fps difference between those two rifles.

With a factory load from Federal, with 200gr Sierra Game Kings (hey, a friend gave them to me! ), the difference wasn't so large.

A-Bolt
2726
2756
2809
2732
2717

M70
2823
2795
2789
2797
(no 5th shot)

I'm guessing that the "slow" RL-25 really needs all 26 inches (plus) to really start to work. Not sure what powder blend Federal was using, but it wasn't as responsive to the extra barrel length.

There! Clear as mud, right?

---

BW:

Actually, quite clear. What started me asking was an article many years ago by a writer gunsmith who asked the same question. He took several rifles he had in his shop for rebarreling, worked up loads, out them through his speed trap, then started cutting off an inch at a time and then testing for speed. He did several, but I only remember a 270 Winchester, a 308 and a 264 Mag. The 264 had a 26" tube. What surprised the writer and me was the fact that the 264 gained velocity - about 200 FPS at 24". It dropped off after that. I believe he took it down to 16". The other caliburs were about what was expected. The 264 was hitting peak pressure before the bullet left the barrel meaning pressure was falling. Cutting the barrel put the peak pressure where it was supposed to be. I wasn't about to cut the barrel of my new beauty becasue I'm curious. I do have a batch loaded that I clocked. I'll run them through the new rifle as soon as the weather lets up. My range it my back yard so the first nice day, the chrono will come out.

I played with Reloader 25 last season. My regular powder was Reloader 22. I've been reloading for 30 some odd years. I've tried different powders, but R22 has alway out performed them. R25 looks to be at least a head above R22. Whe my old 300 started opening up groups, the switch to R25 close the up. But only for six round. That got me through the Colorado Elk season and through the Whitetail season here in North Dakota. No Elk, but a clean kill on a young doe the last day of the season. (I didn't get drawn for a buck.)

Your results on the factory ammo are predictable. I haven't fired factory ammo in my guns for over 30 years. I was given a box of 300 Winchester by a guy I worked with. I pulled the bullets and weighed the powder on my RCBS scale. There was a 5 grain spread in the charge lightest to heaviest. It would have been interesting to run the rounds for speed. But then, simple physics says that 5 grains less will produce less velocity.

I did keep records of every shot I fired in my old 300 Model 70. It took 5000 round before accuracy fell off. When it fell off, it fell off the same way a cartoon character falls off a cliff: Sudden and fast. My one inch groups wents crazy. I had trouble keeping them on a 14" X 14" target.

Thanks for the input. I do believe I will be happy with a 26" barrel. I'l be even happier when I get the action I sent to Rocky Mountain Rifle Works back with its new cutom tube. It's my first venture into custom barrels. I expect great and wonderful things.

Roger

I've only been reloading about 9 years, and since you've got me beat, I've got a question for you.

Can you recall, just how long the Alliant Reloder series of powders has been around? Maybe not all of them, but back it the early '90's, I had the impression RL-22 was sort on new. Was I wrong?

By the way, like you, RL-22 was my 300WM powder of choice, before I tried the RL-25. Do you plan on sticking with the slower powder now?

Thanks!

quote:

---

Originally posted by BW:
Say Rodger,

I've only been reloading about 9 years, and since you've got me beat, I've got a question for you.

Can you recall, just how long the Alliant Reloder series of powders has been around? Maybe not all of them, but back it the early '90's, I had the impression RL-22 was sort on new. Was I wrong?

By the way, like you, RL-22 was my 300WM powder of choice, before I tried the RL-25. Do you plan on sticking with the slower powder now?

Thanks!

---

BW:

Alliant used to be Hercules. I can't remember when the change was made. Late 80s early 90s sounds about right for the change, but I wouldn't swear to it. It seems to me that R22 is failry new. I remember reading an article after Norma MRP disappreared. The powder was imported. The company had problems getting import approval or some such bureaucratic foolishness. The article touted R22 as a powder close to MRP, so I tried it. It took me 6 rounds to come up with a load. R25 was almost as easy. I'm going to stick with R25, if it agrees with the new rifle.

Try the 26" barrel, then cut it off if you don't like it...You can't go the other way and put it back on....

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com