Less Powder, More Speed?

[alcesgigas]

Late in the summer I assembled the completed segments of my 338 Edge and commenced load trials. Most of the time I had a friend along--there were three different persons--and used two different chronographs. We all observed the unlikely phenomenon as follows:
95 gr. H1000=low 2600fps
94 gr. H1000=high 2600fps
93 gr. H1000=mid 2700fps
92 gr. H1000=average 2836fps
91 gr. H1000=high 2700fps
All were OALed @ 3.785 and Remington and Nosler brass/Sierra and Berger 300 gr. with CCI BR2 primers
When weather halted structured shooting--and moose season began--I had worked through the first phases of COAL "best." I went from 3.892 (on lands) in the suggested hunting increments--and stopped at 3.834. All loads were Berger/Nosler/CCIBR2 and the progression showed group size decreasing as I stepped away from the lands.

Now I'm either dyslectic--or my rifle is--anyone have ideas on this anomaly?

 

[D.ID]

Those are extreme variances but it happens. I always suspect the chronograph even three different ones that where calibrated while the stars were aligned and my horoscope said it was my lucky day. However in my 338 edge (unique at 24") I went up to 94.5 grains with the 300s and with each .5 grains I gained about 25fps consistently untill 92 then a huge jump up of 75fps then 50fps then it dropped way back down and the last couple charges rivaled about 88 grain loads in fps and hammered primer pockets. FPS can get extremely inconsistent in an overloaded case. Including going down as the charge goes up. I currently run 89.0 grains of h1000 behind a 300smk in rem brass, on a cci250 out of a 24" for a true 2781 fps. Chronographs lie but gravity and brass life will tell you the truth.

 

[375fan]

What distance were the chronograph screens from barrel when testing loads? Should be 15 foot minimum, 20 is better. Too close and blast will give some funky readings. I like new batteries every time in my chronograph, weak batteries will contribute to funny readings, also angle sunlight or cloud cover allows light to hit screens will affect readings. I have seen some strange readings at times, I always retest loads if they have strange readings just to see if a pattern appears or if strange readings were an anomaly.

 

[alcesgigas]

Screens were (several variances) between 20 and 50 feet. Led lighting was used in the final shooting sessions.

The rifle:
M70 Classic Stainless w/Hart 30" BR1000, the only video showing shooting through chronograph screens has an avi. file extension and thus I cannot attach it here. But I can show off my rifle...

Thanks for your comments.

 

[backwoods83]

Start over at 89grns and use WLRM or Fed215M primers and I bet the speed keeps picking up until you find pressure. I like CCI BR2 primers but not for 90+ grns of H1000, it seems as if the higher you go in charge weight the harder it is to light it off, I'm surprised you didn't get any hang fires. I switched from from CCI250s to fed215Ms in my 300wby hunting stick and the 88grn charge of H1000 with 215Ms was faster than 89.5grn with CCI250s.

 

[alcesgigas]

One of my friends who observed (and is a handloader) suggested I switch to Federals. So when I came down here to Fairbanks last I bought a large box of Federal Gold Medal Large Rifle Magnum Bench Rest; I'm thinking that would be FGMLRMBR215? Apparently I've been mistaken all these years thinking that bench rest primers were a step up from magnum primers. I primed 106 once fired Nosler cases. Returning home tomorrow I'll finish loading them and maybe shoot some this weekend or earlier. It will be interesting because although the temperatures are warmer than normal they've not been higher than -15 F for the last two weeks--with wind.

I'll walk my loads up in two three shot segments from 89.5 gr. H1000 until either the accuracy or pressure--or both--deteriorate. I think I'll bracket the best combination with increments of .2 gr. and see what happens.

Thank you for blindly confirming my friends advice--it sunk in now!

 

[backwoods83]

You are correct my friend, federal gold metal match 215 mag primers are the match grade mag primer, I just shorten it to fed215M. CCI BR2s are just CCI 200s with better consistency due to quality control, 250s are CCIs only large rifle mag primer and they work good, but don't quite have the light off of 215Ms, especially when the temps are way down. The winchester large rifle magnum is also a good subsitute in a pinch.

 

[alcesgigas]

Many thanks to all whom responded; it was sage advice. Federal Magnum 215 Match primers not only brought up my speed, but ES shrank too. I've added some new reloading equipment into the mix and consistently replay Shawn Carlock's video on handloading the Edge. Both my chronographs are on line now too and I'm shooting the first loads of Bertram Brass/M215M/H1000/Berger; less than 50 to go and the hundred I bought will be fire formed to my chamber. Now my edge averages 2852 FPS using 91.5 at 3.960 OAL (can't remember the COAL which is still changing in my search for the "sweet spot."

 

[old_heli_logger]

That's a beautiful rifle! Too bad someone put the bolt on the wrong side )