Been working on loads for my Rem.700.338LM. I'm using 250grn SMK with Lapua brass and FGMM primers. So far I've tried RL-19...About 1.25in.5 shot groups. H-1000 same...RL-22 hovering around .75 to 1in. I see most everyone has 27 to 29 in barrels on their Lapuas, but mine is only 24in. looking for suggestions on what to try next. I was going to try RL-25 and Retumbo, but its getting tough to find powders when needed for testing and expensive to buy a can of powder and it doesn't work out. It may be I'm at the best this gun will shot already, but I never settle if I think there is something out there that works better.
Re: >338LM powder choices for 24in barrel?
Given a bullet (you have one) and a powder (you have at lest 2) a skilled reloader should be able to find a load that works in the gun at hand. {assuming that the chamber,... was accurately machined,...}
Since your gun has a short-ish barrel for a 338 LM, it will probably not respond to the recipies that you will find on the net. This means that you will have to develop a load by yourself for your gun.
You should run an experiment to find where pressure signs first show up by loading up a series of cases (1 shot each) with increasing charge weights. Seat the bullet well from the lands (0.030 min) but not really far from the lands. Start with the powder of choice at the recommended min in your reloading book, then step by 1% to max recommended. Shoot these ONLY for pressure sign information.
Once you see a pressure sign, back down 2% and search this area for an accuracy node in 0.3% steps with 5-shot groups. This experiment should span -3.3% through -0.7% from the pressure sign.
Take the best 5-shot group from this set, then span this new area with 0.1 gr steps and 5 shot groups to verify that the original group was good, and then to determine the width of the charge weight that still shoots good. This experiment in 338 LM (near 90 gr) should consist of at least eight 5-shot groups. With any luck the accuracy node will be wide enough to throw and go at the loading station.
After finding this accuracy node and production tollerance, you can run the bullet seating experiments to optimize the load at hand and finish tuning the load to your gun.
Watch for pressure signs very carefully and religiously--be safe and you WILL find a good load for your gun.
Given a bullet (you have one) and a powder (you have at lest 2) a skilled reloader should be able to find a load that works in the gun at hand. {assuming that the chamber,... was accurately machined,...}
Since your gun has a short-ish barrel for a 338 LM, it will probably not respond to the recipies that you will find on the net. This means that you will have to develop a load by yourself for your gun.
You should run an experiment to find where pressure signs first show up by loading up a series of cases (1 shot each) with increasing charge weights. Seat the bullet well from the lands (0.030 min) but not really far from the lands. Start with the powder of choice at the recommended min in your reloading book, then step by 1% to max recommended. Shoot these ONLY for pressure sign information.
Once you see a pressure sign, back down 2% and search this area for an accuracy node in 0.3% steps with 5-shot groups. This experiment should span -3.3% through -0.7% from the pressure sign.
Take the best 5-shot group from this set, then span this new area with 0.1 gr steps and 5 shot groups to verify that the original group was good, and then to determine the width of the charge weight that still shoots good. This experiment in 338 LM (near 90 gr) should consist of at least eight 5-shot groups. With any luck the accuracy node will be wide enough to throw and go at the loading station.
After finding this accuracy node and production tollerance, you can run the bullet seating experiments to optimize the load at hand and finish tuning the load to your gun.
Watch for pressure signs very carefully and religiously--be safe and you WILL find a good load for your gun.
Re: >338LM powder choices for 24in barrel?
Thanks for your input, but been there done that. I've done my work at the reloading bench on this one as I do on everything I've reloaded in the last 30 years. That is why I have resorted to posting as I figured I must be missing something with this Lapua.
One thing I failed to mention is that I have been held to seating depth because of the length of the mag. I really want to be able to mag. feed this weapon if possible and that hurts me when looking for the best seating depth. I was hoping by posting here that someone else has came across this problem and might have found that a faster or slower burning powder then what I have tried already was the ticket.
The cost of reloading this thing might also be one of the forces behind me looking for a shortcut to finding the perfect load.
Thanks again for your knowledgable answer.
Thanks for your input, but been there done that. I've done my work at the reloading bench on this one as I do on everything I've reloaded in the last 30 years. That is why I have resorted to posting as I figured I must be missing something with this Lapua.
One thing I failed to mention is that I have been held to seating depth because of the length of the mag. I really want to be able to mag. feed this weapon if possible and that hurts me when looking for the best seating depth. I was hoping by posting here that someone else has came across this problem and might have found that a faster or slower burning powder then what I have tried already was the ticket.
The cost of reloading this thing might also be one of the forces behind me looking for a shortcut to finding the perfect load.
Thanks again for your knowledgable answer.
Re: >338LM powder choices for 24in barrel?
I just worked up a load for my Rem 700 MLR 338 Lapua.
Lapua brass
Sierra 225gr soft point(hunting load)
Win mag primers
88.0gr IMR-7828SSC
I just looked at Hodgdon's 2009 reloading mag and they list this load .5 grains under max for your 250gr bullet. They list it as 83-88.5gr for a 250gr bullet.
Hope this helpes
I just worked up a load for my Rem 700 MLR 338 Lapua.
Lapua brass
Sierra 225gr soft point(hunting load)
Win mag primers
88.0gr IMR-7828SSC
I just looked at Hodgdon's 2009 reloading mag and they list this load .5 grains under max for your 250gr bullet. They list it as 83-88.5gr for a 250gr bullet.
Hope this helpes
Re: >338LM powder choices for 24in barrel?
I had good luck with H4831SC. Started at 88 grains and worked up to 91 grains for a tad over 3000 fps with 250 Sierra BTHP. It was a stiff load but accurate. The only 5 shot group I tried was .450. Mostly, I spent most of my time with this cartrige at 1000 yards on steel........TRG42 BTW
I sold the rifle after realizing it was consuming too much of my shooting budget.LOL I had acumulated 1600.00 in brass and bullets in a two week period and was still on the hunt! Just like CRACK, this Lapua Magnum. hehehe.
I had good luck with H4831SC. Started at 88 grains and worked up to 91 grains for a tad over 3000 fps with 250 Sierra BTHP. It was a stiff load but accurate. The only 5 shot group I tried was .450. Mostly, I spent most of my time with this cartrige at 1000 yards on steel........TRG42 BTW
I sold the rifle after realizing it was consuming too much of my shooting budget.LOL I had acumulated 1600.00 in brass and bullets in a two week period and was still on the hunt! Just like CRACK, this Lapua Magnum. hehehe.
Re: >338LM powder choices for 24in barrel?
I have a 20" barrel on .338LM I shoot Retumbo and 300gr.SMK's and get awesome groups.
I have a 20" barrel on .338LM I shoot Retumbo and 300gr.SMK's and get awesome groups.
Re: >338LM powder choices for 24in barrel?
I would recommend the slowest burning powder you can find. I use RL25 for my 338LM. Have tried RL22, Retumbo also. Found that RL25 gives the best velocity and result. With a 24" barrel, you are going to sacrify a little bit of velocity, but a good load has to do with barrel harmonic. Goo luck.
I would recommend the slowest burning powder you can find. I use RL25 for my 338LM. Have tried RL22, Retumbo also. Found that RL25 gives the best velocity and result. With a 24" barrel, you are going to sacrify a little bit of velocity, but a good load has to do with barrel harmonic. Goo luck.
