300WM Faster Than Expected

So, for those who commented on my Bone Head Mistake thread, I did not use the blended H1000/H4831SC for what I'm about to say!

Doing load development on a factory Christensen Ridgeline, after following factory break in procedure using factory Hornady 180gr Superformance ammo. I loaded up some 210gr Bergers in new ADG brass, Federal 215 LRM primers, .040" off lands, .002" neck tension, and a new 1lb can of H1000. Berger book says max load 75.5 at 2804fps, I know it's not always gonna match but it's a good average expectation.

Shooting conditions: Temperature 60⁰F, Humidity 25%, Elevation ~500', Wind 8mph WNW.

5 Shot groups, measure speed with Garmin Xerox C1

Charge Avg FPS SD ES
74.7 2894.5 8.0 22.0
74.9 2904.8 6.9 20.4
75.2 2925.1 5.3 14.8
75.5 2928.1 4.6 14.3
75.8 2938.5 17.5 49.4

All shots grouped horrible but there seems to be a decent node at 75.2 and 75.5 but those groups were 1.5"-2" though.

First I'm curious as to why my results are so much faster than book? Never had any signs of pressure but maybe a slightly sticky bolt on the 75.8 group. Was hard to tell as the action on this Christensen is a little tight naturally after a fired round. Second can I wrangle this load in by adjusting seating depth?

I know all rifles are different but I have a Bergara 300wm that loves this recipe so I used it as a starting point. With that rifle, doing seating depth tests, the worst groups were around .80"-1.0" and when I finally settled on .040" off the lands I could get .50"-.60" groups as long as I did my part with 75.8gr of H1000.

What barrel length are you shooting, and what barrel length is your load data referencing?

i wonder if twist rate makes any difference on velocity as a faster twist might show signs of pressure (given both are chambered with the same reamer, using same brand and lot of brass and same lot of powder)? what i will say is depending on case capacity it could have a lower capacity that what berger used/inputted (they use quick load) as that will give higher pressure with same bullet @ same coal. given that i've been reloading for 40 years it might not mean much! what i've learned on this forum from other reloaders is either i don't know much or i have no reason to change the way i reload. kinda tough to fix something that ISN'T broken . almost seems that not 1 single person on here reloads the same, but might have the same practice. finding the/a good node is good, now work on seating depth to shrink the group. you might not get the/a group of what you'll like as either the barrel doesn't like the bullet or the powder used (can be both)?

dfanonymous said:

What barrel length are you shooting, and what barrel length is your load data referencing?

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Factory Christensen Ridgeline 300WM with a 26" barrel and 1:10 twist. I will have to look at the book again but I believe it is also a 26" barrel they reference.

ARlife4me said:

i wonder if twist rate makes any difference on velocity as a faster twist might show signs of pressure (given both are chambered with the same reamer, using same brand and lot of brass and same lot of powder)? what i will say is depending on case capacity it could have a lower capacity that what berger used/inputted (they use quick load) as that will give higher pressure with same bullet @ same coal. given that i've been reloading for 40 years it might not mean much! what i've learned on this forum from other reloaders is either i don't know much or i have no reason to change the way i reload. kinda tough to fix something that ISN'T broken . almost seems that not 1 single person on here reloads the same, but might have the same practice. finding the/a good node is good, now work on seating depth to shrink the group. you might not get the/a group of what you'll like as either the barrel doesn't like the bullet or the powder used (can be both)?

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Berger says 1:11 or faster and I'm running a 1:10 twist. This gun may very well not like the H1000 or Bergers but my SD and ES are pretty good at 75.2 and 75.5. Will see if seating depth can close up that group.

Everything can make a difference. How tight the barrel is, how many round that are through it, the internal finish of the barrel, brand of brass and its internal volume, bullet brand and bearing surface length of the bullet, lot # of power, brand and lot # of primers, seating depth, neck tension, barrel twist and length, altitude, temperature, humidity, barometric pressure.....it all adds up one way or the other. What you should go by, is exactly what you said, "every gun is different". Some like to shoot at lower velocities and some at faster. Rifles are like women; some are very finicky and some are not. Matter of fact, I've called a couple of my finicky rifles names that are just the opposite of what you'd call a female that's not.

The 210gr 30 caliber Bergers are VLD bullets.
At your stated seating of 0.04" off the lands, I'm not that surprised at your group sizes.
For all my rifles the VLDs like to be up close and personal to the lands 0.005".

As for the speed. Some barrels are faster, some slower. There's really no rhyme or reason.

jstanton said:

So, for those who commented on my Bone Head Mistake thread, I did not use the blended H1000/H4831SC for what I'm about to say!

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It wouldn't have made a hoot of difference if you did.

As to your velocity, I have 5 300WM rifles, all of them get 2950-2990fps with 210's & 215's without any issues, my Rem 700 LR gets 3010fps with Berger 210g VLD, this rifle is always faster and likes slower powders.

Cheers.