Lapua 155 Scenar - 308 win advice

Bolivar

Bolivar

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Hey all

I'm going to try to work up a load good for 1000 yard shooting with my Remington XCR Tactical 308 (factory barrel) using 155 Scenar & RL15

Is there a consensus whether to jam or jump? I have read that some bullets quite tolerant of differences in OAL relative to the lands but I don't know of this bullet is.

I am not worried about fitting these into the mag. I intend these to be a single load round.

Any experienced advice is appreciated. Thanks
 
Cannot help you with RL15, have been using Varget for several years.
First thing to do is to establish the chamber length, boltface to ogive contacting the leade. This will give you a base measurement. Factory chambers tend to be long throated. I suspect you will find that a round loaded with the Lapua, which is close to the lands, is not going to go into the magazine. I know that I cannot load a Scenar with a cartridge length suitable for the factory magazine without compressing the charge so much that the bullet nose is marked up by the seating stem.
Bullets like the SMK tend to be rather forgiving with respect to jump, VLDs, less so.
Be careful jamming. In the event of a cease fire, you can leave the bullet in the barrrel, and spill powder all through the action and trigger mechanism.
 
We have feedback from many top shooters and will offer standard reloading advice. Try various OALs to see what works best in your rifle. Many jam hard into lands while others go .008". There is no set OAL.

Regards,

Peter
 
Factory Remington chambers have infamously long throats. Don't be surprised if your loaded ammo is 2.95" or 3.0" long (this will be *way)* too long to fit the magazine).

A Lapua 155 is a very good choice of 155 grain bullet to try to reach the lands in a Remington chamber. In fact it is the only 155 I can think of that even has a remote chance of being able to do this.

My experience with the Lapua 155 is that it can be quite fussy, accuracy-wise and velocity standard-deviation-wise, to variations in charge weight or bullet seating depth.

I would suggest that you spend some time finding out exactly where your lands are (ie what overall length you need to load to to touch the lands). My first choice would be to try to find a full power load with the bullet .020" off the lands that shoots well. If that doesn't work I would try moderate jamming, about .010" (you want enough jam to be assured that every single round is jammed, you don't want so much jam that you might pull a bullet out if you have to unload an unfired round).

For 1000 yard shooting you don't have very much flexibility - you need very good accuracy, you need near max velocity, and you need very uniform muzzle velocities. If you are able to get these with the Lapua 155, you will have a top-tier 1000 yard 155 load.

It is possible that you might be unable to get the Lapua 155s shooting with a reasonable amount of effort; they are an extremely high quality, high performance and accurate bullet, but they can be fussy at times (I mucked about for *years* with no-better-than-middling results, before I finally was able to get first rate performance from them). If this happens you might want to try another bullet. Whatever other bullet you try it is important that it be very jump tolerant, because in your factory Remington chamber you will have enormous amounts of jump. The best non-Lapua-155 bullet I can think of trying would be a Berger 155.5 Fullbore. It is similar quality and similar ballistic performance to the Lapua 155, but I think quite a bit more expensive. Also, the B155.5 handle jump quite well.
 
Daniel

That is exactly the sort of advice I was looking for. Thanks. I am expecting to have to do some trial and error but I am patient. I could even hang in for two or three trips to my range and "waste" 20 or so rounds in development :D

Okay, I'm kidding a lot. Likely this will be a long term project but I have no real rush. I'm no particularly interested in "competing" in F-Class but rather participating. There are a couple of long range practice dates coming up over the summer at Borden that I want to get in on and try something different.

I have been working to date mostly with the 155 Gn Amax but with generally low muzzle velocity and erratic performance at 1000. I am hoping that the better BC of the Scenar will be enough to keep me well super sonic to 1000.
 
Get her up to 2,900 fps and you'll be supersonic to 1,000yds.
I'm loading the same bullet with Varget and a short throat which slightly compresses the powder. Load is jammed into the lands giving me groups in the .2's @ 100yds. Will try it this weekend at Connaught and see how it does. Never tried this bullet at long range before.
 
In my experience, the Scenar gives significantly better wind performance at 900m than the SMK.
A friend is shooting moly'd Scenars at 3100 with excellent results.
 
I just got my new rifle put together and it was throated with 155 scenars in mind. I've only had it at 100yds so far for load development, which ended up being 45.6grs Varget and it was jumping 10thou. Hopefully it shoots well at longer ranges for me, but it did a .261" 5-shot group at 100yds with this load.
 
Hi tiriaq, if you have more details about your friend shooting Scenars at 3100 I for one would be interested. I was never able to find a hot load for 155 Scenars that worked well (meaning, delivered good accuracy and also good velocity uniformity). When I finally did get 155 Scenars to work well for me it was a 2950fps in a 30" barrel. But with #2155 "old Sierra 155s" I get very very nice results with a typical "46 grains of Varget" 3025fps load.


The OP's rifle is a Remington XCR Tactical 308, which as far as I can tell has a 26" barrel. He may or may not be able to get 2900fps, but if he is able to get good accuracy (say, 5-shot 100 yard groups that average 0.7" or less) and good velocity unformity (10+ shot velocity standard deviations of 15fps or less, or extreme spreads of 45fps or less) with a nice max load, I would think he'll be happy at 1000. Then again with the really long throat in his rifle his combustion chamber is probably 0.2" longer than mine, which will probably really help him make up a bit of extra velocity...
 
rnbra-shooter said:
Hi tiriaq, if you have more details about your friend shooting Scenars at 3100 I for one would be interested. I was never able to find a hot load for 155 Scenars that worked well (meaning, delivered good accuracy and also good velocity uniformity). When I finally did get 155 Scenars to work well for me it was a 2950fps in a 30" barrel. But with #2155 "old Sierra 155s" I get very very nice results with a typical "46 grains of Varget" 3025fps load.


The OP's rifle is a Remington XCR Tactical 308, which as far as I can tell has a 26" barrel. He may or may not be able to get 2900fps, but if he is able to get good accuracy (say, 5-shot 100 yard groups that average 0.7" or less) and good velocity unformity (10+ shot velocity standard deviations of 15fps or less, or extreme spreads of 45fps or less) with a nice max load, I would think he'll be happy at 1000. Then again with the really long throat in his rifle his combustion chamber is probably 0.2" longer than mine, which will probably really help him make up a bit of extra velocity...
Click to expand...

Job one will be to pick an OAL (maybe 0.005 or 0.010 jump) and test some rounds to develop a max powder charge/velocity. Currently with 46.5 RL 15 and 155 Amax I am getting about 2750 fps which results in sub-sonic at 1000 occasionally (I am likely right on the ragged edge all the time at that distance). I'm not sure what the max charge will be. Alliants manual lists 45 gns but their web site lists 49 (not using the Scenar). The Hornady manual gives a max charge of 47 Gn (have to double check that number again) for 155 Gn bullets.

I plan to work slow in small increments and check velocities, primers etc to see how it goes. With my 26 inch barrel, I am thinking 2850 - 2900 fps would be a max I should be looking for. Turning out 3000 fps in this length barrel might be asking too much to be safe.

Once I get that, I will test for groups and see if seating depth helps tune things in. I am not going to spend my whole summer fussing at 100 yards. If I get something that seems promising I plan to get some testing/practice at 1000. It is always a learning experience.

I really should try some with Varget later this summer too. Seems everybody regards this a go to powder for this bullet weight and cartridge. I also see Alliant has a new powder called MR-2000 which they claim will give 3000 fps from at 24 inch barrel. Who knows, might bear a look.

As with most things related to shooting, there are many, many options to explore.
 
Who sells the scenars. I live in ottawa and can't remember seeing them anywhere. I'm pretty sure Lebaron doesn't stock them. Also, what is the approximate cost for these?
 
We have seen N150 deliver the best SD, V and accuracy, although N140 may be tops, as N150 is may be too slow in some rifles. Just saw 46+ grains of N150 only produce 2925 fps in Lapua case with Berger 155.5 in new 30" barrel. Chronograph was PVM-21.
 
I have established my OAL to the lands using the Laupa bullet to be 2.974. I set this by soft seating the bullet in a finger tight case neck, repeated to check for consistency. I then smoked the bullet and did not see rifling marks.

Screwing the seating stem down lightly to the touch the bullet then allows me to measure the overall die length and I can use this to adjust the OAL for later experiments (a competition seating die with graduations would be a lot easier)

I'll either use this OAL or a small jump for initial testing to determine if I can get close to 2900 fps using RL15/Fed 210/Norma case without pressure signs.
 
Bolivar your method of locating the rifling is good. It is important that the bullet not be pressed against the rifling with much more than finger pressure (otherwise you'll be jamming the bullet in a surprising amount). I'll bet those 2.974" loaded rounds look really out of whack next to a 2.80" magazine-length .308, eh? One practical matter is that you probably won't be able to hold your ammo in a .308 ammo box, you'll need to use a .30-06 box.

Peter I think with such a long OAL he might actually have enough room in his case for N150 (wonderful powder, very bulky; I never could get enough of it into my cases, given my much shorter Obermayer chamber, in which 155 Scenars touch the rifling around 2.84" COAL)

Bolivar best of luck with your testing, let us know your results!
 
rnbra-shooter said:
Bolivar your method of locating the rifling is good. It is important that the bullet not be pressed against the rifling with much more than finger pressure (otherwise you'll be jamming the bullet in a surprising amount). I'll bet those 2.974" loaded rounds look really out of whack next to a 2.80" magazine-length .308, eh?
Click to expand...

Yeah, and they only barely eject at than length too.

rnbra-shooter said:
One practical matter is that you probably won't be able to hold your ammo in a .308 ammo box, you'll need to use a .30-06 box.
Click to expand...

I had not thought of that....luckily I have some Magnum length boxes that are not currently being used.


rnbra-shooter said:
Bolivar best of luck with your testing, let us know your results!
Click to expand...

Yup, will do.
 
Playing hooky on a sunny Friday afternoon can be a lot of fun

I loaded 10 rounds with the bullet basically just touching the lands, varying the powder charge by 0.2 gns to see how velocities and pressures looked. Temp was about 20-25 C I would estimate. The velocity results are as follows:

46.2 Gn 2819 fps
46.4 Gn 2798 fps
46.6 Gn 2855 fps
46.8 Gn 2867 fps
47.0 Gn 2863 fps
47.2 Gn 2878 fps
47.4 Gn 2910 fps
47.6 Gn 2908 fps
47.8 Gn 2948 fps
48.0 Gn 2965 fps (slightly compressed charge - won't rattle in the case)

All extracted fine, primers maintained rounded edges. The firing pin impacts were dimpled slightly, getting more so with each progressive charge. I was "shooting" for 2900 fps so I think that 47.4 and 47.6 Gn seem like a good place to check for repeatability. I am afraid of reading too much into 10 samples of one shot each so I don't want to get aggressive with my powder charge. I could run into problems on a really hot day.

I did keep my target but at 100 yards the vertical difference hard to see. Also, after 5 or 6 rounds the impacts started to drop which I expected to see. I proper ladder test would have to be done at greater distance but I don't know if/when I will get a chance for that.

Hopefully I will be able to get back and test some loads for groups later this weekend, if the weather holds good.
 
At the range today. I loaded 10 rounds each with 47.4 and 47.6 Gn RL15 with an OAL of 2.974 (touching the lands). Measured run-out was less than 0.005 for all the rounds tested. Brass is Norma neck sized with a Lee collet die.

47.4 Gn load
Average: 2938 fps (in the ball park of my previous test)
ES: 43.4 fps (2912-2955fps)
SD:15.65
5 shot groups 0.96 in and 1.12 in. Roughly superimposing the two groups gave a 10 shot group of 1.3 inches

If I include the single round test from Friday (2910fps), ES goes to 45 fps

47.6 Gn load
Average: 3026 fps (more than 100 fps faster than my previous test)
ES: 95.26 fps (2989-2084)
SD: 27.47
5 shot groups 1.29 in and 0.67 in. Roughly superimposing the two groups gave a 10 shot group of 1.7 inches

It would seem that 47.6 Gn is actually a bit too much since I had high ES/SD. The fact that the velocities jumped 100 fps from my previous single shot test concerns me. If I were to include single shot from Friday (2908fps), the ES actually increases to 175fps

Moving forward I am going to assume 47.4Gn is the max. Average velocity/ES/SD seem okay based on earlier advice on this thread. The next thing to try with this component combo would seem to be OAL.

I was thinking I should try jamming to a max of 0.010 and jumping to a max of 0.020? What sort of increments should I be using. Is 0.010 to course? Is 0.005 too fine?

If that does not work, try primers next? I have worked with Fed210s to date has they seem to give me better accuracy that the WLRs I have been using for years. Maybe try Fed210m or CCI-BR?
 
Just thought I'd share my data if anyone is interested. I have mine loaded with an OAL of about 2.824, which in my rifle is about a 10 thou jump to the lands. I use 45.6 grains of Varget with CCI BR-2 primers and Lapua brass. These were my velocities today:

2964
2958
2957
2961
2950
2955
2966
2967
2972
2961

Giving me an ES of 22 and a SD of 6.44. I've been really happy with how the rifle has been shooting, so hopefully it continues to do so!
 
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