Accuracy loads for custom 300 win mag w/180 & 190 gr MK

[Sunny]

My wife of 30 years has been my accomplished big game hunting partner & really snapped me off with a custom 300 win mag for our 30th wedding anniversary! What a Gal!!! I would deeply appreciate your pet-load, accuracy based reloading information for this type of rifle. I am still breaking in the 26" Krieger fluted match grade barrel in #5 contour, which is set on a Winchester Mod. 70 BDL post-war action that was trued & lapped. The Monte Carlo stock is pillar bedded & the trigger has been reworked to break at a crisp 2lbs w/o any creep, which is truly outstanding. I am currently using up my stock of old reloads that didn't shoot very accurately in my other 300's, however, I am very impressed with the sub moa groups these "old" various loads are now consistently producing in this rifle & am anxious to make-up some real accurate target & hunting loads, which are known to work in premium match grade barrels for the 300 win mag using the sierra match king and game king bullets in 180 & 190 gr. My Krieger barrel has a 1 in 11 twist, which I believe should be ideal for both "hunting & competition style bullets" in this 180 & 190 grain range. I am new to this site but not new to reloading... From my past experiences with my other rifles, these Sierra MK's usually prefer to be seated .010 off the lands, where as the Berger VLD's demonstrated the best results touching the lands. I have experienced temperature related problems in my other rifles with the IMR & RL powders, whereby my chrony identifies quite substantial fps variances that is also recognized in group size variances. Accordingly, I am considering using H4350 or H4831 powders to correct this problem. In closing, I only use Federal Match Grade primers, however, I just can't seem to justfy the cost of Lapua brass... I use WW or RP brass, which I separate accordingly. Kindly advise & I thank you in advance.

 

[Guest]

Favorite load out of my .300 Win Mag is 76 grs. IMR 7828 using a 180 gr. Scirocco bullet w/F215 primer. A 190 Sierra MK would have to "hump it" to beat this combo as it shoots sub MOA all the way to 1000 yds. This is in a rifle that has a blueprinted M70 CRF action and what some would consider a "lowly" Douglas premium barrel in #5 contour! I wish I had a few more of these "lowly" Douglas tubes!!

You may not can justify the Lapua brass but IMO it's the most consistent brass available. However....this particular chamber likes any brass you stick in it! Yep...think I'll order me a couple more of these "lowly" Douglas barrels!

 

[BountyHunter]

69-73 gr H4831SC depending on which brass and F210 primer is top load several 1k shooters with 210 bergers.

69-71 gr H4350 is good load to start with also.

Brass is cheap, buy RWS and it will outlast the barrel and is most uniform brass on the market.

BH

 

[sewwhat89]

What kind of velocity do the H4831 and H4350 give with the 210s?

I am shooting 73.5-75 gr of RL 22 with the 190 Berger VLDs with great results. Velocity is from 2820-2920. I have shot up to 77 gr, but groups started opening back up. I never hit excessive pressure.

Bullets were seated 0.005" into the lands. I have some H4350 that I was gong to try with my 300 SAUM, but I will try some loads as you suggested.

 

[BountyHunter]

barrels are 30" and MV is pushing 3000 and in some cases over. Most will find an accuracy node in the mid 2900 range though.

BH

 

[leslie naylor]

Give RL19 a try.
I load nosler 180bt & 190smk with 72g and nothings complained.
Also both loads show no pressure indications,this is with lapau brass.