High 300 win mag velocities

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dead meat

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I'm doing load development on a Winchester m70,26" barrel 300 win mag for a friend. Loaded up test loads with the following results, 180gr Hornady interlock bullets and RL 22 powder, Labradar was the cronograph started at 73 and worked up to my working loads.
1---74.5 grs-3068
3067
3053
2---75 grs- 3077
3063
3058
3--75.5 grs-3134
3122
3169
All cases were R-P except for the last, it was a PMC i used by mistake, flattened primer all others looked normal. From the groups i like the 74 gr load. Haven't done load work on a 300 win mag for sometime and that was without a crono so going by the books i wasn't expecting that high of velocity. Going to try some H4831 today if the wind stays down, also have Sierra 180 gr gameking bullets to try. I have a large stash of H870 i could try, a favorite in my 264 win mag. Any input guys, are the velocities ok?
 
What is your objective- are you looking for top accuracy or top velocity?

If you get higher velocity than reload data suggests then your pressure will be higher also to some degree. I have 300 winmag that gets 150 fps more velocity than published data says it should. The crono tells me this rifle has minimum chamber and I should use published data conservatively in this rifle.

I was loading for a friend's rifle I wouldn't push the pressure envelope too hard. Aim for factory ammo velocity or slightly better and leave good enough alone.
 
With 190 horandy 75gr gave me 3100 with the same gun. I did a slow work up to 80gr never seen any presher signs. But enough is enough. One of the best rifles I ever sold. Dam!!!
 
Rifle is friends deer and moose rifle, he will be loading his own ammo once we determine a good load he's happy with. Time to teach him how to reload. I see Alliant list RL 22 and a 180gr bullet at 77grs at 3055fps out of a 24" barrel. Of course many variables occur, it is rocket since after all. Small rockets. :d
 
Looked at Hornady 9th. With their 180 grain, they show max of 76.0 grain of RL-22 - showing as 3,000 fps - using Hornady/Frontier brass, Win WLRM primers in 25" Rem 700. You do not mention what primers you used, you are using different brass (and apparently seeing the consequences of swapping that out) and a longer barrel, but you must be quite close to what they were getting??

Velocity is for bragging about; accuracy is for hitting what you aim at.
 
Was looking some more. Hornady 180 flat base have B.C. about .425. So, start at 3,000 fps from 300 Win Mag, have 30-06 muzzle velocity about 115 yards down range. So 115 yards more "reach" than standard 2,700 fps from 30-06. So the additional "roar" and "buck" from 300 Win Mag only really gains when a 30-06 has quit - that is actually a very long way down range?? Bullets likely need 1,800 fps to reliably expand. 450 yards with 180 grain 30-06. 115 yards more with 300 Win Mag. A very long way for most hunters.
 
A well-made rifle does not show pressure signs until into proof pressure range.

Velocity is a surrogate for pressure. You can measure velocity.

If velocity is adequate (and book "max" is adequate) then find accuracy and be done with it.
 
Personally I'd spend the extra few bucks and buy a premium bullet too. I will probably spend the equivalent of 2 boxes of premium bullets just in gas getting to/from my moose hunt this year, plus tags and everything else... I was going to use the Interbond for moose this year but decided to try the GMX instead in a different rifle.
 
More results, this time with H4831 and a mix of sierra and hornady bullets.
70grs H4831
#1-2758
-2754
-2763-- 180 gr Sierra 2.5" group
71grs H4831
2-2802
-2803
-2801-- 180gr Hornady .75" group
72grs H4831
3-2855
-2846
-2861----180gr Sierra 1" group
72.5grs H4831
4-2890
-2846
-2861 ----180 Sierra----2" group
Rl22 and Hornady gave much more consistent groups of 1.25 to 1.5 " overall. Will go back and retry 71 and 72 grs H4831 and both brands of bullets but they look good. Cases are all RP and primers are Rem 9 1/2mag. Velocities are below Hodgdons and less than factory Rem 180gr published figures. May load up some H870 for ####s and giggles just to see what it does. Hodgdon only lists 1 load of 86 grs and Lee goes up to 89grs. A lot more powder for no gain. Sorry for the omitted info in original post.
 
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Some of your results in Post #9 - you do not list the powder loads. There are at least two powders listed in Nosler #7 with 180 grain bullets over 2,800 fps from 24" 30-06, and you are using a 26" 300 Win Mag? Might be perfectly safe loads there, but a lot of powder going down that bore for not a whole lot of improvement? Sierra #5 tops out with 180 grain bullets and H4831 SC at 70.7 grains powder for 2900 fps, with a 26" Savage rifle. They do however list their accuracy load as 71.6 grains of IMR-4831 at 3,000 fps from the same rifle.
 
Your velocities seem entirely in line for a 26" barrelled .300 Win with 180s. I expected 3150 fps with 75 grains and a decent barrel. I moved away from it and toward H1000 for tighter ES and a measure of temperature insensitivity.
 
Dogleg said:
Your velocities seem entirely in line for a 26" barrelled .300 Win with 180s. I expected 3150 fps with 75 grains and a decent barrel. I moved away from it and toward H1000 for tighter ES and a measure of temperature insensitivity.
Click to expand...

This.

Any 300 Win Mag that really only gets 3000 FPS (kind of agreed upon book data) from at 24” barrel with 180s is cursed as far as I am concerned.
 
Went out yesterday with a few more loads i wanted to retry, 71grs H4831--2825
2837
2830
73grs H4831--2917
2904
2920
then tried H870, old Hodgdon book says 86 is max, Lee book says 89 is max, load i tried was 84grs---2841
2760
2844
All these loads were with 180 gr Sierra Gameking, accuracy is not as good as the 180gr Hornady,so i think that is what we go with. RL22 looks to be the powder we use as well. I thought H870 would perform a little better, may have to crono my old 264 win mag loads, they are very accurate in my Sako and a custom my dad had built in the 60's.
 
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