300 Win Mag accuracy

[holl]

I have a sendero weight 26" shilen 1x10 barrel. vais brake. bedded in fiberglass McMillan stock, 200 rds. jewell trigger. shooting off benchrest.

Id like to shoot 178g Amaxs and have been working up loads with H4831SC.
what speed would you think would be the node? I'm currently at 3000 fps and think I need to slow it down. Ive tried R22. Changed the bedding a couple of times.

Also, how often should I clean it? I know all barrels are different, but this thing seems to want to be cleaned after 8-10 rds. Is that normal?

is there any reason I shouldnt expect it to be a .75 moa rifle?

 

[Steve Blair]

I shot a 28" .300 Win in the eighties with Sierra 190 MK at ~3000. It was very accurate and would go a complete course without cleaning. (~75 rounds) Some barrels are pickier than others but 8-10 seems a bit too touchy. What happens when you shoot more than that? Do groups open up? Velocity spread increase?

 

[holl]

I think the groups open up, or at least flyers show up. I have not shot it over chrono to determine what happens with more shots. I did a ladder test and saw nothing really strange, velocity wise, in 10-12 shots. . It does better before the barrel heats up. Which is why I rebedded it. Now I'm thinking it just fouls quickly....

so 3000 fps for a 178g. isnt too fast?

 

[Steve Blair]

Some powders burn pretty dirty until they reach full pressure and your load is moderate, probably about 55k. There is nothing wrong with that but may not produce optimal burning. I run H4831SC in both .284 Shehane and .300 WSM with 180 and 230 grain bullets, respectively. It burns clean when running at full pressure. I have no experience at reduced pressure, maybe someone else can contribute their experience. [br]
No, it is not too fast. I would expect that 3100 is about where I'd look for full pressure. As always, rifles are individuals and what is safe in one may not be in another. Work up carefully to locate your pressure bounds. You might also try N160 and N165. Although a little pricey, both are clean burning and temperature stable. Good luck.

 

[holl]

Steve, I have a bunch of H4831SC and use it in my .284 Win in F class. So I want to use that.

thanks for the input.

 

[Steve Blair]

How about a heavier bullet? Your rifle probably has a twist close to 10" and can handle it.

 

[holl]

I have a stack of 178 amaxs... trying to use what I have

 

[Steve Blair]

Good strategy, these days.

 

[Alex Wheeler]

How fast are you shooting? Factory barrels can have a tendency to walk. If the gun starts throwing shots after 8 rounds, I'd just put a new barrel on it, I have wasted enough components and time trying to get bad barrels to shoot. Sometimes its cheaper to just fix em up front.

 

[ShootDots]

Holl, if you have some H1000, give it a shot... A .300 is a B-I-G case. I shot MANY .300 Wins and H4831, although a GREAT powder, in my opinion, is better suited to 150-165 class bullets in that case. Try H1000 and "run it up there"! It burns VERY clean at top pressure, and velocity will WAY surpass H4831 in 180+ class projectiles!! T-Rust me on this one!!

 

[holl]

Z fast- its a custom barrel and I agree about replacing vs. time, effort....
I will try some H1000 if I can find it.

 

[Raythemanroe]

Just my opinion, I would think 178g Amaxs at 3000 fps is a little slow for a 300wm! I have had better luck with clean burns at hotter temps Pretty much what ShootDots said!

 

[benchracer]

Hodgdon load data shows IMR 4831 and IMR 4350 as the top velocity producing powders for your chosen bullet weight in .300WM. Both powders produce 3100+ in a 24" barrel according to Hodgdon.

IMO, you need to do two things: (1) Establish your rifle's preferred seating depth with this bullet. (2) Test all the way to max.

Every rifle I own shows an accuracy node at or near max.

As you shoot up your 178's, you really should consider going with bullets in the 200+ grain weight range and Retumbo. That combo will give you all there is to be had from this cartridge with currently available powders and bullets.

 

[hogan]

I have a sendero weight 26" shilen 1x10 barrel. vais brake. bedded in fiberglass McMillan stock, 200 rds. jewell trigger. shooting off benchrest.

Id like to shoot 178g Amaxs and have been working up loads with H4831SC.
what speed would you think would be the node? I'm currently at 3000 fps and think I need to slow it down. Ive tried R22. Changed the bedding a couple of times.

Also, how often should I clean it? I know all barrels are different, but this thing seems to want to be cleaned after 8-10 rds. Is that normal?

is there any reason I shouldnt expect it to be a .75 moa rifle?

Think your expectations are very reasonable. Also concur with the advice to use a 200gr or heavier bullet.

Look at the Sierra manual and try one of their accuracy loads.

Do you own a Wilson case gauge or an RCBS Precision Mic? These will show you oal changes in case dimension. Belted magnums really need to headspace on the shoulder. Did Shilen do the barrel installation on your rifle? You need to know what your brass is doing.

Try neck-sizing only and don't FL size until seating loaded round requires some effort.

Your scope or scope mount setup may be the culprit. Be sure your mount screws are not over torqued and ascertain that the scope is concentric to bore and that its reticle movement is precise. Your scope rings might not be holding. Were they lapped? Try another scope that has worked on another rifle.