264 mag vs 7mm mag

[BeeTee]

Hey Bee Tee. The problem once again was I couldn't get the bullets up to speed in the 7 mags. No way no how. Noslers book data is very cold for the .264 as you probably already know. Several powders will push the 120bt over 3400 from 26" barrels in the .264. In my sons 27" barrel 3500 is in reach. I still have no doubt in shooters with 7 mags getting the velocities they claim they are getting. Guy Miner for one is getting great velocities out of his Ruger #1 7 mag. If he told me he saw a cow flying over mt St Helens I would take his word for it. He is also aware that I tried 3 different 7 mags with the same results-low velocities.

I just have a problem with blanket statements like "The 7 mag is superior to the .264 and loading manuals prove it". In the real world it doesn't work. reflex264

I didn't say it... The loading manuals don't prove it either, but they do offer reasonably unbiased if not perfect data.

First, someone would need to define the word "superior". If it's all about trajectory and energy on target, we'd all be shooting the 338 Snipe-Tac - or something similar.

In the end, if we're happy with what we're shooting, that's what counts. I've daydreamed about a 6.5 Rem Mag for a long time (the 264's little brother). A Rem 700 short-action with a slim 22" barrel and lightweight graphite stock would make a sweet/easy carry antelope rifle. Till then, my Rem 700 7RM will have to do. Jim

 

[Oldtrader3]

Reflex, in the real world, the .264 and 7mm Rem Mag (small, over-bore magnums) vary a great deal from one rifle to another. My 7mm Rem Mag custom Mauser shoots the 160 grain (.283 SD, .475 BC) Nosler Partition bullet a 100 fps faster (3080 fps) than Scottie's .264 shoots the 140 Nosler Partition (.286 SD). This despite the manuals stating that they should be nearly identical for muzzle velocity. I have also seen several 7mm Rem Mags that would not shoot the 160 Partition bullet faster than 2800+ fps with the same load, primer and powder, etc.

This is always the problem with strictly using empirical data. Plus, with the small bore magnums each individual rifle seems to operate independently of any statistical prognostications of performance for that rifle in experiments. I was an engineer for 40 years and did many experimental and statistical studies which never seemed to match what empirical data told me that I would get for results. You really need to shoot several different rifles of each caliber with slightly variable chamber data and the same load data in order to create a realistic profile of that caliber's performance with the set of parameters.

In addition to theis issue, ballistic coefficients are somewhat theoretical and are velocity dependent, displaying coefficient decay as velocity diminishes and approaches the speed of sound. You are having a degree-of-freedom issue effect on data sets with your experiments and need more sample rifles to eliminate this issue.

 

[okie2]

Hey Bee Tee. The problem once again was I couldn't get the bullets up to speed in the 7 mags. No way no how. Noslers book data is very cold for the .264 as you probably already know. Several powders will push the 120bt over 3400 from 26" barrels in the .264. In my sons 27" barrel 3500 is in reach. I still have no doubt in shooters with 7 mags getting the velocities they claim they are getting. Guy Miner for one is getting great velocities out of his Ruger #1 7 mag. If he told me he saw a cow flying over mt St Helens I would take his word for it. He is also aware that I tried 3 different 7 mags with the same results-low velocities.

I just have a problem with blanket statements like "The 7 mag is superior to the .264 and loading manuals prove it". In the real world it doesn't work. reflex264

I didn't say it... The loading manuals don't prove it either, but they do offer reasonably unbiased if not perfect data.

First, someone would need to define the word "superior". If it's all about trajectory and energy on target, we'd all be shooting the 338 Snipe-Tac - or something similar.

In the end, if we're happy with what we're shooting, that's what counts. I've daydreamed about a 6.5 Rem Mag for a long time (the 264's little brother). A Rem 700 short-action with a slim 22" barrel and lightweight graphite stock would make a sweet/easy carry antelope rifle. Till then, my Rem 700 7RM will have to do. Jim

Jim
I hate to spoil your dream but the 6.5 rem mag needs a 26" barrel too I have 2 of them
and it runs right beside the 264.
For volocity it beats the 6.5x284 and the 6.5-06.

 

[BeeTee]

Jim
I hate to spoil your dream but the 6.5 rem mag needs a 26" barrel too I have 2 of them
and it runs right beside the 264.
For volocity it beats the 6.5x284 and the 6.5-06.

I can't think of an antelope/deer/elk rifle cartridge that wouldn't benefit from a longer barrel.

Back to the topic.... When comparing the 264 to the 7RM, it needs to be in the same length barrels - to be fair.

I still think a light/compact 6.5RM in a short action would be cool.... :wink:

 

[reflex264]

Reflex, in the real world, the .264 and 7mm Rem Mag (small, over-bore magnums) vary a great deal from one rifle to another. My 7mm Rem Mag custom Mauser shoots the 160 grain (.283 SD, .475 BC) Nosler Partition bullet a 100 fps faster (3080 fps) than Scottie's .264 shoots the 140 Nosler Partition (.286 SD). This despite the manuals stating that they should be nearly identical for muzzle velocity. I have also seen several 7mm Rem Mags that would not shoot the 160 Partition bullet faster than 2800+ fps with the same load, primer and powder, etc.

This is always the problem with strictly using empirical data. Plus, with the small bore magnums each individual rifle seems to operate independently of any statistical prognostications of performance for that rifle in experiments. I was an engineer for 40 years and did many experimental and statistical studies which never seemed to match what empirical data told me that I would get for results. You really need to shoot several different rifles of each caliber with slightly variable chamber data and the same load data in order to create a realistic profile of that caliber's performance with the set of parameters.

In addition to theis issue, ballistic coefficients are somewhat theoretical and are velocity dependent, displaying coefficient decay as velocity diminishes and approaches the speed of sound. You are having a degree-of-freedom issue effect on data sets with your experiments and need more sample rifles to eliminate this issue.

I agree 100%. My fortune has been better with the .264s.
Emperical data vs. real world results is always going to result in disagreement. Consider the way that Nosler achieved their results for the .264 for use in their manual. The .264 had a 24" barrel. In real life I have seen two .264s with a 24" barrell. Most of them around here 26" factory jobs or 27" or 28" customs. Nosler used powders that are typicaly too fast for good results in the .264 and they already know that. IMR7828, RL25, Magnum, Magpro and Retumbo all generate much better results. I still don't understand not using those powders. Others have and got pressure work done with much better results. reflex264

 

[okie2]

they can always make things look good on paper.
This is why I quit buying gun magizines 35 years ago.
But we all know better now.
In time the truth always comes out.
I'll stick to my 264 26" barrel and reloader 22
and my NOSLER BULLETS

 

[Oldtrader3]

I agree with you Reflex on the powders which are listed in the manuals for the small bore magnums being too fast for the case to bore ratio. Most of my experience has been with the 7mm Mag and the rifle which I currently own is a 24 inch barreled Mauser. Using IMR7828, I am happy to attain 3080 fps with the 160 Partion or AccuBond in this barrel length. I would be happier with a 26 inch barrel but what is done is done and until this barrel's throat is eroded, it will stay 24 inches.

However, when I bought my .340 Weatherby, I persisted on getting a 26 inch barreled model and with it velocities from handloads in this rifle equal published factory load muzzle velocities which is usually a challenge with the Mark V in anything but a 26 inch barrel. I finally learned my lesson.

When the 22 inch barreled Model 70's Westerners came out in 1962, I was really intersted in the .264 Mag cartridge but did not want a 22 inch barrel and never did buy one for this reason. I bought my first 7mm Rem Mag instead in a Husqvarna (23-1/2 inch barrel). This imprinted me for the 7mm Mag and I have owned one ever since I replaced the Husky with my present 7mm Rem Mag Mauser in 1976.
Charlie

 

[Gm weatherby man]

Heh, my GMC goes farther and longer than the rest. :twisted: :twisted: :lol: