Anyone shooting the 256 flatlines in 338LM?

[Fursniper]

Sure would appreciate hearing from anyone using the 256 flatlines in your lapua magnum. Your thoughts, experiences with these bullets, any load data you could share, all would be appreciated!

 

[Supersubes]

Dan Warner recommended h1000, so I went with that. In my AXMC, true OAL at "touching" is 4.127". Way longer than my magazine. Single feed only. I was jumping them .050" with 92.5 gr of h1000 for 2900 fps. Accuracy is good, no issues with barrel fouling, the Drop/drift is spectacular as you may imagine. I'm kinda done with .338Lm so I really never gave them the workout they deserved. I'm waiting for the components to chamber up a 300 norma barrel, and will be shooting the 198 Flatlines.

 

[Fursniper]

Dan Warner recommended h1000, so I went with that. In my AXMC, true OAL at "touching" is 4.127". Way longer than my magazine. Single feed only. I was jumping them .050" with 92.5 gr of h1000 for 2900 fps. Accuracy is good, no issues with barrel fouling, the Drop/drift is spectacular as you may imagine. I'm kinda done with .338Lm so I really never gave them the workout they deserved. I'm waiting for the components to chamber up a 300 norma barrel, and will be shooting the 198 Flatlines.

Curious why you're giving up on the lapua.......?

 

[Supersubes]

I just think the Norma is a better solution. The lapuas length precludes loading anything to magazine length. When I load 285 eld's, the plastic tips take a hammering on the front of the magazine, which kind of defeats the purpose of shooting really high BC bullets. Part of that may be due to the AI brake, which isnt very effective. Even if I return to the bore size, I'll likely do it via the norma case, or a shortened lapua.

The 300 norma with a flatline should easily out perform the lapua. Barrel life will be decreased significantly, but I do my own chambering so thats an easy fix.

 

[Fursniper]

I just think the Norma is a better solution. The lapuas length precludes loading anything to magazine length. When I load 285 eld's, the plastic tips take a hammering on the front of the magazine, which kind of defeats the purpose of shooting really high BC bullets. Part of that may be due to the AI brake, which isnt very effective. Even if I return to the bore size, I'll likely do it via the norma case, or a shortened lapua.

The 300 norma with a flatline should easily out perform the lapua. Barrel life will be decreased significantly, but I do my own chambering so thats an easy fix.

Thanks Supersubes. I gave the Norma serious consideration (Frank sure talks it up) before starting on this new Lapua build but yeah, the barrel life held me back as I really shoot alot. Additionally, friends are not having great success with the Norma brass life (primer pockets) compared to the lapua brass. I figured with some wind in the equation and being able to load long with a heavier bullet, the difference in performance would not be that great? How far out do you feel the 300 Norma will be effective for you? If you were to single feed your lapua without the limitation of the magazine, do you feel you could have improved it's performance at distance?

 

[lash]

Hey Fur. As you know, I've been using the 256 Flatlines in my .338 LM for a while now and am quite happy with the results. Yes, it's true that I have to single feed them, but since I am only using them for distances in excess of 1200 yds and that only a few times per year, I'm not phased by that limitation. I'm pretty sure that you and I PM'ed a bit after my last outing, where I was able to make it to 1840 yards before I ran out of time (we had to be out of there by 3:00 pm). Using the Flatlines, I was able to make three consecutive hits within a 17" "group".

I think that I was at about 16.4 mils to make those hits. But I am only running them at a relatively slow 2945 fps (94g H1000, 0.020" off lands) since I have a short chambered factory Savage 26" barrel. There are number of guys making 3100 fps+ without any trouble using longer cut rifled barrels.

I'm definitely a fan of both the .338 LM cartridge and the Flatline projectiles. I just like to shoot that big gun. On the other hand, at some point, probably towards the end of this year, I'll buy a bunch of the new 6.5 122g Flatlines and see about taking my .260 to 1760 and beyond while staying supersonic. It's expensive fun, but it's great fun!

To paraphrase Buzz Lightyear (I have grand-kids), "To 1760 and beyond!"

 

[lash]

Oh yeah, and at less than 50' ASL here in Florida I'm pretty happy that the published 0.450 G7 BC worked out about perfectly in my simple Ballistic app. In the morning, when it was cooler, I had to add a tenth or so to the shorter distances 1200-1400, but as the day warmed up, the predicted calls were spot on w/r/t elevation. I kept my loads in a cooler bag (without ice or cooling) because I wanted to see how they performed without the added pressure of sun baked loads. Another time, I might compare the results between temperature controlled rounds and some left in the sun.

 

[Fursniper]

Oh yeah, and at less than 50' ASL here in Florida I'm pretty happy that the published 0.450 G7 BC worked out about perfectly in my simple Ballistic app. In the morning, when it was cooler, I had to add a tenth or so to the shorter distances 1200-1400, but as the day warmed up, the predicted calls were spot on w/r/t elevation. I kept my loads in a cooler bag (without ice or cooling) because I wanted to see how they performed without the added pressure of sun baked loads. Another time, I might compare the results between temperature controlled rounds and some left in the sun.

Hey Lash, thanks, yeah I had forgotten you were using the 256's but then I'm lucky these days to remember to leave the house fully dressed lol. Just trying to do some ideas on loads & bullet choices while waiting for McMillian to finish my stock, all the other pieces parts are ready to go. I've got a spot out to 2500 yds not far from the house so it's going to be interesting to see what the new rig can do. I love shootin' the big guns too, been having some fun with a 375CT out to 2500 while waiting for this build completion, what a gas to shoot! A friend may be buying a pair of "big eyes" like they use at KO2mile so we can actually see results better at 2500.

I'm glad to hear the flatlines are proving out to their bc, I should be getting my 300 bergers out to a mile around 14 mils (my DA here is much higher than Florida!) so I'm hoping the flatlines will give me some reasonable hope & consistancy for hits on demand out past 2000. Barrel is a 30" bartlien so I'm hoping....just gotta figure how hot I can run 'em.

I may try the new 6.5 FL'S out to a mile too. I've had pretty good success with my 260 out that far with the 140 hybrids (if the winds not too bad) & those are only doing around 1100 fps when they hit. Should be easy if a guy could stay supersonic.

Thanks again for the reply & your load info. Let me know how you like those new 122's!

 

[Supersubes]

Thanks Supersubes. I gave the Norma serious consideration (Frank sure talks it up) before starting on this new Lapua build but yeah, the barrel life held me back as I really shoot alot. Additionally, friends are not having great success with the Norma brass life (primer pockets) compared to the lapua brass. I figured with some wind in the equation and being able to load long with a heavier bullet, the difference in performance would not be that great? How far out do you feel the 300 Norma will be effective for you? If you were to single feed your lapua without the limitation of the magazine, do you feel you could have improved it's performance at distance?

The brass life is a concern, and one area the lapua flat out shines above everything else. I went back and forth about wildcats based upon the lapua case. I'm pretty sure i'll revisit the case at some point. The norma made things pretty easy since everything is easily available, like the lapua. On paper, it should offer a few hundred yards of extra supersonic range. Not night and day really, just something extra.

Regarding the 256's. I never loaded those to mag length. Not sure thats possible given the short bearing surface. That would also mean .300" bullet jumps i think. 2900 fps for my gun was the safe year round good brass life load. There's certainly more there if I want to hotrod it.

 

[lash]

I seem to remember that some guys were posting loads as high as 98-99 g H1000 with speeds around 3200, in the older 256 Flatline load thread on Scout, but I'm not even sure if that site is still up to go check.

 

[Fursniper]

The brass life is a concern, and one area the lapua flat out shines above everything else. I went back and forth about wildcats based upon the lapua case. I'm pretty sure i'll revisit the case at some point. The norma made things pretty easy since everything is easily available, like the lapua. On paper, it should offer a few hundred yards of extra supersonic range. Not night and day really, just something extra.

Regarding the 256's. I never loaded those to mag length. Not sure thats possible given the short bearing surface. That would also mean .300" bullet jumps i think. 2900 fps for my gun was the safe year round good brass life load. There's certainly more there if I want to hotrod it.

Thanks for the reply, that's interesting what you said about the short bearing surface. I don't have experience with these yet so it's going to be a journey of discovery & interesting. Once you get the Norma going, looking forward to hearing if it meets your expectations and what you think of the 195's. I've wondered too what the "quintessential" wildcat would be based off the 338 case without going crazy overbore....

 

[Fursniper]

I seem to remember that some guys were posting loads as high as 98-99 g H1000 with speeds around 3200, in the older 256 Flatline load thread on Scout, but I'm not even sure if that site is still up to go check.

I'm going to run them as hot as I can without sacrificing brass life too much, just won't know until I start loading them, where pressure signs are going to show up, etc. At $2.50 a pop for brass I don't want to get TOO crazy.... On the other hand, if I could get to 2500 without going to an improved case, well, knowing me, I'll probably push them lol. Where does this "sickness for distance" ever end.....??

 

[lash]

It looks like someone moved some of the load info over from Scout:

https://www.snipershide.com/shootin...it/elr-beyond-1000-yards/6252792-256-flatline

Edit: I take that back. Only one load listed.

98.7g H1000 at 3150 fps MV

 

[Fursniper]

It looks like someone moved some of the load info over from Scout:

https://www.snipershide.com/shootin...it/elr-beyond-1000-yards/6252792-256-flatline

Edit: I take that back. Only one load listed.

98.7g H1000 at 3150 fps MV

Thanks lash, I'll take whatever info I can gather...!

 

[Tjfarmer]

Lash, what savage are you shooting? I saw in another post it's a 10 twist barrel, my ba is a 9, just wondering. I got 100 on the way to try out. Thanks.

 

[Supersubes]

You can see from the caliper photo that there are several contours along the bullet. The nose, just forward of the major diameter, engraves partially. Whole lotta nose on these things.

The other photos are 300 norma dummy's I put together before ordering a reamer. I'm only posting these so you can get an idea about the bullet profile. The two cases pressed down on the bullets are fl sized .308's. Graphic example of how little full groove depth bearing surface they have. The 230 berger looks pretty underwhelming next to the 198. If I magazine lengthed a 256 in a lapua, I might lose the bullet down inside the case LOL. Never tried seating them short.

I dont recall exactly how fast I got the 256 to go. Seems to me it was around 3025 or so. The data above looks an awful lot like Jeffvn's load. Pretty sure he's shooting an improved lapua case though, not standard. That load would be a grenade in my AXMC.

 

[Dan Warner]

Just a little addition here to help you guys out... Jeffvn is running an improved case and 101g of H1000. The unimproved cases will not get that much in it; 96g is about it maybe 97 after running the compacter over it. Just to add to the point of topic, we have many folks running this powder in the Lapua case at around 94g. Many are not on this forum, hence the lack of response from them. If I sent you load data to start with, you know there are better powders for this cartridge though, in terms of burn rate. Accessibility and inventory are of course issues when trying other powders, so if it works and is in hand already, all the better.
If you are looking for 300 Norma details, we have a reamer already made for the 198 Flat Line combo. It was released for general sale by JGS many months ago. Email us at the shop and I'll send you the print if you are interested. Might save you from having to do all the leg work of designing it.

 

[Fursniper]

You can see from the caliper photo that there are several contours along the bullet. The nose, just forward of the major diameter, engraves partially. Whole lotta nose on these things.

The other photos are 300 norma dummy's I put together before ordering a reamer. I'm only posting these so you can get an idea about the bullet profile. The two cases pressed down on the bullets are fl sized .308's. Graphic example of how little full groove depth bearing surface they have. The 230 berger looks pretty underwhelming next to the 198. If I magazine lengthed a 256 in a lapua, I might lose the bullet down inside the case LOL. Never tried seating them short.

I dont recall exactly how fast I got the 256 to go. Seems to me it was around 3025 or so. The data above looks an awful lot like Jeffvn's load. Pretty sure he's shooting an improved lapua case though, not standard. That load would be a grenade in my AXMC.

Nothing like visuals to get a point across , thanks!

 

[White Mamba]

98.7 is my load, I have a 32inch barrell though

 

[Fursniper]

98.7 is my load, I have a 32inch barrell though

Standard lapua or improved?

 

[White Mamba]

Standard