Need Load Data for 338 Lapua Mag

[Tazer]

Took a while but finally have all the components to reload my 338 Lapua Mag. I had been using Hornady 250grn BTHP and have been unable to obtain. Went to Cabela's Saturday and scored 100 rounds of Hornady 285 grn BTHP. For powder I like IMR 7828 and scored 2 lbs of the IRM7828scc. Have new brass, Hornady, and primers, CCI Magnums. What I'm missing is load data and C.O.L. My 7th edition of the Hornady reloading data book only goes to 250 grns. I hate guessing at loads, especially using different components. I've researched IMR reloading guide and others but unable to find this exact component mix. Can anyone help? Also, when I study data for larger grain bullets the weight of the powder goes down, in my example, about 2.7 grains per 25 grains of bullet weight. Can anyone help me with that. Either or would be great. Heading to the mountains in 2 weeks and will site in at 200yds then can go out to 500yds.

 

[Koinonia]

From Hornady 8th Edition.

Sorry about it being upsidedown~!

Did you want the 285Grn Bullet data, too?

285Grn BTHP - SD:.356 / Dia:.338"
BC: 0.720 COL: 3.625"
(There is no listing for using the 7828 Powder with this weight bullet, but the burning rate is between H1000 ((slower)), and R22((faster)).)
Low - 2400 FPS , Max - 2750 FPS
R22 - 72.9g Low/ 86.5g Max
Supreme 780 - 74.9g Low/87.7g Max
R 25 - 77.2 Low / 89.6 Max
H 1000 - 77.2g Low/ 89.6 Max
Retumbo - 81.7g Low/ 93.0g Max

 

[rsayloriii]

Here's what I've got in the 49th Edition Lyman Reloading Handbook.


Sent from my RobCo Pip-Boy 3000.

 

[Tazer]

Thank you both. The info included will help tremendously especially the C.O.L. Looking at the Lyman Reloading data it recommends a max load of the 275grn bullet at 81 grns of powder and the 300 grn bullet at 80 grns. Given this information I should be at max load at 80.5 grns. Does that stand to reason? I'm just an amature so bare with me. Just a little picture to add to the fun. This is my DAD's press. My brother kept it and believe it or not a .30 cal. shell holder and a universal shell holder, when I showed interest in reloading he gave me the press and the rest is history. Use them both for my .308's and .338's.

 

[Koinonia]

Tazer, Assuming in Reloading can be very dangerous. I'd suggest starting at the lowest listed, or even better, 5% under the lowest, and work your way up until you see pressure signs, or you get the best accuracy, whichever comes first.

It may not be the most fun, but neither is standing over an exploded gun.

 

[Dawico]

Use the load data for the 300gr bullet. Don't try to guess at an unlisted max load.

A max load is very seldom the most accurate anyways.

Be careful.

 

[rsayloriii]

Definitely go with the powder charge for the higher weight bullet. Work your way up from there until you get the results you are looking for. Given for what you're looking for, you might go up or down in charge until you find the spot that YOUR rifle likes.

As a disclaimer, the max loads listed are generally conservative, but as stated, max loads generally don't offer the best accuracy.

 

[Tazer]

Thanks for the info. Will start at 76 grains.

 

[TXARGUY]

Don't know if anyone else mentioned this but LoadData.com is also a good resource.

https://www.loaddata.com/members/se...erid=15&header=.33 Caliber Reloading Data

 

[Tazer]

Well fella's, I made my run to the mountains. Target Facing due North, the wind was blowing from NE to SW any where from 5 - 15 mph so we only went out to 100 yds. My loads ranged from 76 grns to 80 grns. None of the cases showed any signs of excessive pressure i.e. primer round, primer dimpled out, case expansion. My groups were pretty shotty. I'd like to know what you guys think I should go with next. More rounds at a given weight to check grouping. I can do this locally.

 

[Dawico]

I would try a different powder. The Lyman book highlights (bold print) what powder grouped the best during their testing. Given that, N170 (Vit) and Magnum (Ramshot) may be good options for testing. I know some powder is very hard to find right now but that is the direction I would go.

 

[Vaquero]

Cartridge Loads - Hodgdon Reloading Data Center - data.hodgdon.com

Good resource. Up to date.

 

[Koinonia]

Well, if you can, seat a bullet into an empty casing by setting the bullet in just enough to keep it from falling out, then set it in the action, and close te bolt to seat it by forcing it into the case from making contact with the rifling. After extracting that dummy round, figure out you COL, then shorten you seating die to match the seating depth, then adjusting it to seat slightly deeper. Then recheck COL by chambering a second dummy round, checking for rifling contact marks until none show, to eliminate some free bore.

Keep upping your charge until you see accuracy improve, or see pressure signs, and back off.

Document everything you do in regards to length, powder, and shot groupings to see what is most accurate.

 

[Vaquero]

Well, if you can, seat a bullet into an empty casing by setting the bullet in just enough to keep it from falling out, then set it in the action, and close te bolt to seat it by forcing it into the case from making contact with the rifling. After extracting that dummy round, figure out you COL, then shorten you seating die to match the seating depth, then adjusting it to seat slightly deeper. Then recheck COL by chambering a second dummy round, checking for rifling contact marks until none show, to eliminate some free bore.

Keep upping your charge until you see accuracy improve, or see pressure signs, and back off.

Document everything you do in regards to length, powder, and shot groupings to see what is most accurate.

Yep, slow and steady. She'll let ya know what she likes.

 

[Tazer]

Thanks for the advise. Will follow through and let you know.

 

[Koinonia]

Thanks for the advise. Will follow through and let you know.

Very cool! It's always nice to see someone getting into the hobby.

Just remember, it is a process, and requires significant effort, and experimentation regarding powder types, weights, cases, and all that lovely stuff. I reload because it is fun to be in absolute control of what goes into my rifle(s). Once you find that sweet spot with powder, and bullet, it just give you an amazing feeling of accomplishment.

 

[Brownman0311]

http://www.lapua.com/upload/downloads/brochures/2012/vihtavuorireloadingguideed10_2012eng.pdf


This group was shot at 200 yards from my Barret MRAD using their accuracy load 88.5 gr of N165 with 250 gr Lockbase bullet. Barrel is 24.5 inch 1-9.4 twist.

 

[Tazer]

Mr. Brownman0311, Thanks for the Lapua download. I wanted to use their load data with my 250 grn. Hornady's but couldn't get any. Went with IMR 7828 and excellent results up to 90 grns. Just for fun I bought some 285 grn Hornady BTHP's to play with and am working up the loads. In your experience since my top load was 80 grns with no evidence of a pressure problem would be interested in your advice. I'm thinking of whooping up some more at 80 grns and taking to Red's for an indoor (no wind) results.

 

[ROGER4314]

I have most of the major loading manuals and found the Lyman 49th edition to be the most conservative. I never post load data but the Lyman book has two pages of data. You won't get into trouble using the Lyman data. I agree with the other guys. Start conservative and work up the load as you go.

Flash

 

[Tazer]

Ok Fella's, I've made a set of 6 rounds, 285 grn Hornday BTHP. My last batch ended at 80grns with no signs of over pressure. Starting at 80grns and going up to 83grns in 0.5grn increments. Will look for pressure problems after each shot. Will report results.