Need help with .338 lapua

[Vicdiesel]

Need help with .338 Lapua load work up.
Loaded some 300gr lapua .338 in Lapua brass jammed in .5 increments from 83 to 92 from.
Given how large the range is, I didn’t want to start down at the low end so I started at 89gr.
First shot produced a pierced primer.
Should I start with a .010 jump or start over at a lower initial charge?

Thanks!

 

[Huskydriver]

What powder?

 

[Harveyn]

I would probably say both. Jamming is going to increase the pressure vs jump. I normally start my load dev 10-20 thou off the lands. Are you experiencing any other signs of high pressure? A pierced primer on it's own does not nessasarily mean you have an overpressure load. More details about the setup would also be helpful. What rifle, barrel, length, twist also what powder, primer etc.

 

[Vicdiesel]

Sorry... H1000
Factory AXMC 30” barrel, don’t know th twist of the top of my head.
Also, yes, heavy bolt lift.
Federal 215m primers

 

[Harveyn]

I would increase your seating depth to 10-20 thou jump, reduced your starting load down to at least 86gr or try a slower powder. I generally like to start on book min and load up 1 round each increasing 1 grain at a time just to figure out what your max charge is. It's a lot easier to explore a charge range once you know what your max is and rougly how much powder you need to achieve your target velocity. I'm having excellent results with Retumbo and Hornady 285 ELDs

 

[Huskydriver]

Sorry... H1000
Factory AXMC 30” barrel, don’t know th twist of the top of my head.
Also, yes, heavy bolt lift.
Federal 215m primers

Axmc didn't come with a 30" factory tube that I know of. Did you mean 20"?

For my axmc with a 20" 338 lm barrel. I topped out at 88.8 grains of h1000 pushing a 300 smk with a smashed primer. Cci mag primers to the lands in nosler brass.

I found retumbo to much better overall at 92 grains.

I could never get near max load data in my axmc fyi. I would jump them .020 and try a couple at 88

 

[Vicdiesel]

New used rifle.. haven’t measured it but it’s far longer then 20”....
It’s stamped milehigh .. as per what they have available right now, it’s at least 27”.
Think I’m gonna pull them and start lower, along with at least a .02 jump.
Thanks for the responses!

 

[GIXXER2000]

I run 90.2 of Retumbo with 300 Hy's on my AI with 27 in barrel. I only use H-1000 for 250 grain bullets. I have mine .02 off the lands and am getting 2743 AVG with an sd of 4. AI-AXMC should have a 27 in factory barrel with 1-9.3 twist

 

[BGH808]

My rig is an AXMC Mav41 27" barrel that has a 1:9.35 twist.
W/Silencerco Big Bore Harvester Sppr
I find that 97grs of Reloader 33
Lapua Brass
CCI 250s
300gr SMKs
3.688 OAL
.20 off the lands
Works the best for me.
.25MOA.
I've taken them out to 1800meters.
The Reloader 33 is a slower burning charge, which works well in the 338LM with 300gr projectiles.

 

[towerofpower93]

My rig is an AXMC Mav41 27" barrel that has a 1:9.35 twist.
W/Silencerco Big Bore Harvester Sppr
I find that 97grs of Reloader 33
Lapua Brass
CCI 250s
300gr SMKs
3.688 OAL
.20 off the lands
Works the best for me.
.25MOA.
I've taken them out to 1800meters.
The Reloader 33 is a slower burning charge, which works well in the 338LM with 300gr projectiles.

What kind of velocity are you getting with that load?

 

[BGH808]

What kind of velocity are you getting with that load?

About 2756.

 

[towerofpower93]

About 2756.

Thanks. Would have thought it higher, based on the RL33, but I guess the barrel/bullet tells us how fast it wants to go to stay accurate.

 

[BGH808]

Thanks. Would have thought it higher, based on the RL33, but I guess the barrel/bullet tells us how fast it wants to go to stay accurate.

Correct. The burn rate of the 33 is much slower[which is a plus for the 338LapMag] than say H1000. I have a recipe for a SMK250 that has a much higher velocity if that is what your looking for.
Lapua Brass
250gr SMK
CCI Mag 250 Primers
103-103.5 charge weight R33
OAL min 3.68
Velocity 3,012 fps
When I'm shooting in competition, I use that recipe. I'm a bit more accurate over 1500m( as long as the windage correction is small)
I use the recipe for the 300s mostly for large game (Elk, Moose) or sometimes in competition when the wind is cooking. I do shoot at high altitude and the temp variation is almost nonexistent...so I can't tell you how R33 reacts to high Temps.
I will say that since it came out R33 has been not only my choice but also every serious shooter I know both military and competition/Hunter that uses the 338Lapua cartridge.
Happy Hunting ?

 

[towerofpower93]

Correct. The burn rate of the 33 is much slower[which is a plus for the 338LapMag] than say H1000. I have a recipe for a SMK250 that has a much higher velocity if that is what your looking for.
Lapua Brass
250gr SMK
CCI Mag 250 Primers
103-103.5 charge weight R33
OAL min 3.68
Velocity 3,012 fps
When I'm shooting in competition, I use that recipe. I'm a bit more accurate over 1500m( as long as the windage correction is small)
I use the recipe for the 300s mostly for large game (Elk, Moose) or sometimes in competition when the wind is cooking. I do shoot at high altitude and the temp variation is almost nonexistent...so I can't tell you how R33 reacts to high Temps.
I will say that since it came out R33 has been not only my choice but also every serious shooter I know both military and competition/Hunter that uses the 338Lapua cartridge.
Happy Hunting ?

Thanks for that info. I picked up a pound of RL33 and Retumbo when I got my 338LM along with a box of Berger 250gr OTMs and Hornady 285gr ELD-Ms. Tried a velocity ladder with RL33 but never saw a plateau with either bullet that was high enough to deal with the reported temp sensitivity, so I moved on to Retumbo.

Might need to revisit the RL33 and go a bit higher to see if there's a way to get the 250s above 3,000fps safely.

 

[BGH808]

Thanks for that info. I picked up a pound of RL33 and Retumbo when I got my 338LM along with a box of Berger 250gr OTMs and Hornady 285gr ELD-Ms. Tried a velocity ladder with RL33 but never saw a plateau with either bullet that was high enough to deal with the reported temp sensitivity, so I moved on to Retumbo.

Might need to revisit the RL33 and go a bit higher to see if there's a way to get the 250s above 3,000fps safely.

Here are some questions you might ask yourself that can also help fine tune performance...
What kind of platform[rifle]are u shooting from? Is your primary elevation extreme, one way or the other? What's the average ambient temperature where you shoot. Do you keep your ammo in a temp consistent container?
These and other factors will effect velocity, trajectory, ect...
I do find that shooting with a Can actually helps with this particular rifle. Today's suppressors do not reduce muzzle velocity. They will not effect your POI either. They do however improve accuracy by stripping away the turbulent gases from the muzzle, which allows for full loads.....and can also alleviate pressure problems(which some reloaders have). I find that I shoot tighter groups over 1000m with a Can.
Food For Thought?

 

[BGH808]

Here are some questions you might ask yourself that can also help fine tune performance...
What kind of platform are u shooting from? Is your primary elevation extreme, one way or the other? What's the average ambient temperature where you shoot. Do you keep your ammo in a temp consistent container?
These and other factors will effect velocity, trajectory, ect...
I do find that shooting with a Can actually helps with this particular rifle. Today's suppressors do not reduce muzzle velocity. They will not effect your POI either. They do however improve accuracy by stripping away the turbulent gases from the muzzle, which allows for full loads.....and can also alleviate pressure problems(which some reloaders have). I find that I shoot tighter groups over 1000m with a Can.
Food For Thought?

Oh, and those Hornady 285 ELD-Ms are a great projectile. I've never had a problem with those bullets...if it ain't broke, don't fix it...good luck?