Range Report 308/198gr Flatlines ELR in MT - results from field

[jbailey]

Josh Kunz at Patriot Valley Arms (PVA) and I have been working on crazy project: a 308 that shoots with, or out-shoots, magnum cartridges shooting the best Berger bullets. Key to this is Josh's/Warner Tool's 198grain Flatline bullet: https://warner-tool.com/collections/flat-line-projectiles/products/30-caliber-198gr

The 308 rifle, built by PVA, is on a Big Horn long action, so it can feed the long 198gr from a magazine (we are using the Magpul 30-06 mag and its great). Barrel is a 8.7 twist Hawk Hill at roughly 30 inches. With Lapua small primer 308 brass and 47.0gr of 2000MR, it drives the 198gr comfortably at 2740 to 2770 fps (depending on temp). The resulting ballistics match/exceed a 300 Win Mag shooting 230gr Bergers, at least on paper.

Here is a picture of the rifle deployed:


Ranges from Vectronic PRLF10. This unit had no problems returning target ranges with repeated 'same range' returns.

Spotting: Leica 15x binos, with spotting by my good buddy Oliver, who is a Montana local and another good buddy, Matt, who traveled with me from Virginia.

Ballistic solutions by my Kestrel 5700 AB. 198gr BC we were using: 0.410 G7 (derived from drag data provided by Hornady, customized to my MV's). MV was solved for dynamically based on the temperature sensitivity of the powder.

We had some issues with the optic on the rifle, which we worked thru, but this was a challenge.

Results: overall very good, I believe meeting the objective of creating a 308 that can shoot ELR with the magnum cartridges shooting the best Berger bullets.

Over 100rds fired against targets 1200yds and well beyond, with nearly all hitting target on 1st or 2nd round, and repeatedly. No problem shooting consistent impacts. Wind of course is the biggest challenge but the bullet wants to hold its line and hits were possible in changing wind conditions. Vertical was not a problem with consistent results on the vertical plain, close to the solutions provided by the Kestrel AB. At 198gr and still carrying nearly 700ft-lbs at 2000yds, splash and impacts are relatively easy to see, a huge factor in ELR shooting.

The load starts to get 'tired' after 1900yds or so. Wind and come-up gets harder here as the bullet is reaching the 1100fps tran-sonic barrier. Hits are possible but not easy.

Longest hit was at 2070yd and it was the first round. The 2nd round fired at 2070yd target also hit. I was not able to hit the final target, at 2150ish yards with the three rounds I sent at it. My buddy Matt, with a 7 SAUM shooting 180gr Bergers did hit it, on his third round. The 308 was right with the 7SAUM thru out the day, so I don't view the 2150yd failure as a NO GO.

Conclusion: Josh and Warner Tool has successfully pushed the ballistic edge with their Flatlines. These bullets clearly result in huge increase in hit percentage, operational range, and consistency.

 

[steve123]

Good conclusion and sounds like a fun time!

How do the projectiles group at your zero distance?

Hmm, I wonder how well they would work in my 30-375R. Sending 225's at 2960 fps currently. That would be one awesome project this winter.

 

[littlehendrick]

Is this a super long throated 308 chamber as well? Or in theory, could someone single load something similar (pending barrel twist rate)?

Either way, fantastic experiment,really cool to see what can be done with a 308 with some outside thinking.

 

[lash]

I read this and started thinking about my .30-06...

 

[bohem]

littlehendrick littlehentye reamer used on both my barrel amd James' barrel is an 0.070" freebore setup for no turn with Lapua brass. The COAL to be 0.020 off a new throat is 3.310 with the 198 flatline.

well done James!

 

[niteshooter]

30-06 seems like it would strike a good balance.
But the mad scientist part in me is curious about these flatlines in a 300 Norma/ ultra mag; 30-378 weatherby, 300 raptor.

 

[Jeffvn]

i ran the 198s in my 30-06 Ackley. Great pills as far as I tried to take them at my desert location (2,100 yards).

Jeffvn

 

[lash]

i ran the 198s in my 30-06 Ackley. Great pills as far as I tried to take them at my desert location (2,100 yards).

Jeffvn

Jeff,
What twist is your 30-06 Ackley? My experience with the .338 Flatlines makes me believe that they prefer a faster than normal twist rate for best results. I notice that James used an 8.7 twist in his .308 for this project. My .30-06 is a standard 10 twist, so am thinking it needs a new, longer barrel with a tighter twist rate.

 

[jfields]

30-06 seems like it would strike a good balance.
But the mad scientist part in me is curious about these flatlines in a 300 Norma/ ultra mag; 30-378 weatherby, 300 raptor.

I run them in a .300 Norma and they are damn impressive. 26" barrel sends them at 3110.

 

[jbailey]

Good conclusion and sounds like a fun time!

How do the projectiles group at your zero distance?

Hmm, I wonder how well they would work in my 30-375R. Sending 225's at 2960 fps currently. That would be one awesome project this winter.

Steve123,
My zero distance is 100yds. The 198gr Flatlines and me are 0.5" capable there across 5 rounds. I have fired smaller groups but not "all day long". This precision was fairly constant across several different powder charges with a good MV SD/ES of around <10/15fps respectively. I had precision issues with the 180gr Flatlines - I couldn't get them to shoot under 1" but honestly didn't try much once I had the 198 working. 180gr Flatline is impressive BC, but the 198gr is out-of-this-world good.

Regarding guys speculating about these pills in bigger, magnum cartridges - obviously my 308 will be dusted by those bigger cartridges shooting the same 198gr bullet. Our objective was to see what we could do with a 308 cartridge - challenge the consensus "308 sucks" on some parts of the internet. At 1800yds, we will gladly put our 308/198gr combo up against 6.5 Creedmore's and the like

If nothing else, we had a helluva good time.

 

[jbailey]

Oh yeah, a few more 'in the weeds' details-

Regarding the 198gr BC... the BC we are using is for the MV's we are getting from 308 (2750-ish). You send these things at magnum MVs - 3000fps+ - and the BC goes up because the bullet's form factor really does well vs the BC model bullet at the higher mach's. The bullet's form factor isn't as hot down in the mach 1.0-1.2 range because here base drag is a bigger component and Flatline's magic isn't in the base, but in the ogives.

Josh might have some different view points RE MV and BC interplay, but I think both him and I are getting fairly consistent ballistic solutions and results.

And finally, I am getting very consistent impacts on the vertical plane - suggesting that the bullet-to-bullet differences (in both MV and BC) are significantly less than swaged bullets. There is a lot less variation between bullet dimension and weights for Flatline vs competition and that really shows up at these long ranges were these 'errors' have more pronounced effect.

 

[Jeffvn]

my 30-06 Ackley wears a 27" w/ 1:9" twist.

 

[bohem]

Jeff,
What twist is your 30-06 Ackley? My experience with the .338 Flatlines makes me believe that they prefer a faster than normal twist rate for best results. I notice that James used an 8.7 twist in his .308 for this project. My .30-06 is a standard 10 twist, so am thinking it needs a new, longer barrel with a tighter twist rate.

lash james and I both use an 8.7tw barrel on our 308s because wehad them on the shelf from Hawk Hill. The 198s specifically call for a 9 twist . The 256s call for a 10minimum rate, this is not for optimal performance to transit the sound barrier but rather the minimum required for stable, accurate flight. The 256 flies just fine from a 10tw but if you want to push it to tue sonic extremes a 9 twist is going to help.

Jeffvn has a 9 twist 3006AI based on my recommemdation for the min required rate of that bullet and all of the ballistics testing done during prototype phase was thru his barrel.

 

[lash]

lash james and I both use an 8.7tw barrel on our 308s because wehad them on the shelf from Hawk Hill. The 198s specifically call for a 9 twist . The 256s call for a 10minimum rate, this is not for optimal performance to transit the sound barrier but rather the minimum required for stable, accurate flight. The 256 flies just fine from a 10tw but if you want to push it to tue sonic extremes a 9 twist is going to help.

Jeffvn has a 9 twist 3006AI based on my recommemdation for the min required rate of that bullet and all of the ballistics testing done during prototype phase was thru his barrel.

Thanks Josh. I appreciate the detailed response. It is good information for anyone who is considering a build specifically focused on using the Flatline solids for extended ranges.

 

[Potss]

Excellent test and results, Warner knows their bullets. I just wish they'd make some that expand/tumble/frag/terminally perform so they could be used for something other than ringing steel at 1200y.

 

[bohem]

Excellent test and results, Warner knows their bullets. I just wish they'd make some that expand/tumble/frag/terminally perform so they could be used for something other than ringing steel at 1200y.

Dan just sent me some 7mm's for a winter testing project with my SAUM hunting rifle. I need a day of focused time to do some test cutting once I get back from MT myself.

So far we have had folks send in some photos of animals killed with them in states that allow monolithic solids for hunting. The performance has been exceptional, the bullets turn end-over and bend into wicked looking little candy-canes. A couple of DRT muleys and sheep have come from 30c magnums.

I am trying to get setup for a place to do some ballistic testing with my 308 shooting 198s into gels

 

[jbailey]

I am trying to get setup for a place to do some ballistic testing with my 308 shooting 198s into gels

Will email you on this.

 

[jbailey]

Excellent test and results, Warner knows their bullets. I just wish they'd make some that expand/tumble/frag/terminally perform so they could be used for something other than ringing steel at 2000y.

Fixed it for you

 

[MontanaMarine]

Very nice shooting and thanks for sharing.

I like stretching the 308 out too, but I'm not twisted to handle the flatline bullets. They really take the 308 to the next level.

 

[bohem]

Very nice shooting and thanks for sharing.

I like stretching the 308 out too, but I'm not twisted to handle the flatline bullets. They really take the 308 to the next level.

There are 30c flatlines for 9, 10, and 11.25 twist barrels. The 160gr in an 11.25 twist would give you performance like a 260 Rem slinging 140 class 6.5mm bullets

 

[MontanaMarine]

Both my 308s are 1/12. I'm shooting 208s at 2600.

I'd have to go 1/9 twist.....198 or bust.....grin

 

[jbailey]

Both my 308s are 1/12. I'm shooting 208s at 2600.

I'd have to go 1/9 twist.....198 or bust.....grin

Gunny,
first off, you have a beautiful state, hands down one of the top spots in US. Enjoy!

I'm biased on this, but the 198 Flatline is a beast. One thing that isn't reported in the BC number is how consistent the bullets are one bullet to the next. Why is this valuable? (1) the bullets all leave the muzzle at nearly the same velocity - with nearly zero load development, I had no problem getting low single digit SD and high single digit ES across all the powder charges test. (2) the bullets then all lose velocity at the same rate as they fly. Translation: they all hit the same spot on the vertical plane, leaving you the shooter to just worry about the wind deflection. This is huge advantage. Then of course the bullets, given the attractive BCs, deflect in wind less than competition.

Flatlines aren't for high volumes of fire, nor for the stuff under 1000yds, but for beyond 1500yds, they are tough to beat.

 

[Centurion123]

Really not a relevant question at all given how far they fly before going transonic; but do they fare decent at say <1000fps impact speed? Does twisting them up with say an 8 twist help? I will buy them for my 1-9 300WM no matter what though, just asking out of curiousity.

 

[Jeffvn]

Centurion123 - I've shot them from my 30-06 Ackley @ 2,100 yards. I've never shot them far enough to see how stable they are in transition. Based on the length of the pill, and the fact that I'm running a 1:9" twist (rather then a 1:8 - that will maximize stability through the transition zone) I suspect - BUT DON'T KNOW for sure - that they will not be very stable with the 1:9 twist.

 

[jbailey]

Yeah Centurion123, I would probably agree with Jeffvn. They may have been starting to fall apart on me at 2100yds ... that was at or just past transonic for me at my MV (2750-ish) and DA (5k'). Now this is from a 308, so taking a 308 to just short of 2100yds with consistent hits is impressive in my book.

With your 9 twist 300WM, you are looking at 3000 to 3100fps at the muzzle, depending on your barrel. That will offer significant increase in transonic range over my wimpy 308. You should have good luck with them.

Maybe Josh will clime in.

 

[Dan Warner]

I'll just leave this here for you to chew on.... Just for grins, I ran JBM at a modest 3250fps MV. I'm sure you can run the 198 faster in the 300WM, but this is a good starting point. I used an elevation of 1000 feet, not knowing specifically where Centurion123 is, and it is a fair average for the East coast shooter. Besides, higher elevations will simply have better results anyway. According to JBM, it is supersonic to 2600 yards. Tweaking it to an attainable 3350fps MV pushes it to 2700 yards and if we change the elevation to 5000 feet, it goes to 3100 yards of super sonic flight. For comparison, if we switch to the Berger 230g bullet at 2800fps (same 5000 feet of elevation), you are good only out to 2100yards of supersonic flight. The important thing to note in this comparison is the flight time. 3.61 seconds to the 2100 yard mark for the Berger and 2.72 seconds for the 198g Flat line (4.98seconds to transition point of 3100yards).

 

[Centurion123]

Most of my shooting is up at 4000ft, so the 198s will perform pretty darn good. Running them over a 215/230 Berger is a no brainer, at least for ELR. Thanks for the help guys and for an awesome thread! Really motivated me to try the Flatlines.

 

[bohem]

The twist rates published for the Flatlines are the minimums required for stable, accurate supersonic flight. They're not the requirements for sonic transition. Generally speaking, you need to go about 12-15% faster than the published values for these bullets. It depends on the atmospheric conditions where you're shooting them but for the sake of discussion, twisting up from a 9tw to an 8tw brings you about 11.5% and it seems to have made it possible to squeak them past the sound barrier in a 300 Win Mag that I built for a gent out west. I know that my 8.7tw has issues past 1900yd down here at sea level but when I took them to CO and WY this year at 8000DA I was not having issues with consistency at 2000+, they were still supersonic though.

 

[Farmerbrown32]

Any body have any more info on game performance with these 198 monsters?

 

[jbailey]

Mr @Farmerbrown32-
I do not have any information on the 198gr and terminal performance on game. It sure hits steel hard, and if the deer had class IV armor on, I'm sure the 198gr would get the job done
Maybe @bohem or @Dan Warner has some BDA for us...

 

[Dan Warner]

Nothing first hand...yet. I have feed back from a few folks that say they have done a fine job. I will be testing some Flatlines on some pigs this summer and will report details as we have them

 

[Backspace]

Generally, where do these like to sit off of the lands? Wondering if i would be able to keep them close enough to shoot well and have enough bullet in the neck with a chamber throated for something like a 225 eld.

 

[Dan Warner]

James will have better 1st hand experience on this than I, but they are generally very forgiving in terms of jump. Closer is better in most cases, but we have shot them with good results at a caliber in jump length. In a chamber throated for the 225, you will certainly be jumping them. I'd say it is more important to maintain concentricity and yaw by seating enough in the neck than over getting closer to the lands. That is to say that I'd rather jump them than sacrifice ammo integrity trying to get closer.

 

[Farmerbrown32]

Awesome. Well I will do some testing with them next hunting season and report back. Will shoot some coyotes in the mean time.

 

[Deleted member 113831]

What are the reamer and die specs? Who made them?

 

[Dan Warner]

What are the reamer and die specs? Who made them?

Not sure who you're asking, so I'll add what I know. Flatlines in general work quite well with SAAMI spec chambers because they do not require much throat. Typically, the 198 needs about .115 to .125 of free bore. You don't need any special seating dies either. Your usual preference should work just fine. On occasion, the seating stem will not have quite the correct angle for the ogive and cause damage, but this is rare; only about 2%. Should yours fall into that tiny window, we are happy to correct it at no charge to you; you simply need to send it to us.

 

[jbailey]

Generally, where do these like to sit off of the lands? Wondering if i would be able to keep them close enough to shoot well and have enough bullet in the neck with a chamber throated for something like a 225 eld.

@Backspace-
In general, they like to be close to the lands... or so my very limited experience says. I have not messed with it much, or any other Flatline bullets, so this applies to the 180gr and 198gr .30 only. I don't know how close they are, just that they are jumping a bit and did much better with less of a jump.
Sorry couldn't offer broader view.

 

[Backspace]

@Backspace-
In general, they like to be close to the lands... or so my very limited experience says. I have not messed with it much, or any other Flatline bullets, so this applies to the 180gr and 198gr .30 only. I don't know how close they are, just that they are jumping a bit and did much better with less of a jump.
Sorry couldn't offer broader view.

Thanks for the input. Probably tells me all i need to know. If im going the flatline route, ill probably need to order a new reamer with less freebore. Sounds like the seated long with light neck tension to basically seat the bullet when you chamber it (like whidden did or does) might be worth looking into for the big 30s that will erode a throat quickly.

 

[jbailey]

What are the reamer and die specs? Who made them?

@Skookum
My chamber and dies are nothing fancy. Josh at PVA, aka @bohem did the work with the reamer and its my understanding it his normal .308 chamber (he is both the gunsmith and bulletsmith, so I trust his decisions). The dies I'm using are Redding .308 comp dies, nothing fancy.
The fanciest part of the system are (1) the twist (9 or 8.7 or something fast like that) and (2) its on a long action, so it can load these long 198 way out and get lots of powder in there and still magazine feed.

best regards,
James

 

[Deleted member 113831]

Not sure who you're asking, so I'll add what I know. Flatlines in general work quite well with SAAMI spec chambers because they do not require much throat. Typically, the 198 needs about .115 to .125 of free bore. You don't need any special seating dies either. Your usual preference should work just fine. On occasion, the seating stem will not have quite the correct angle for the ogive and cause damage, but this is rare; only about 2%. Should yours fall into that tiny window, we are happy to correct it at no charge to you; you simply need to send it to us.

@Skookum
My chamber and dies are nothing fancy. Josh at PVA, aka @bohem did the work with the reamer and its my understanding it his normal .308 chamber (he is both the gunsmith and bulletsmith, so I trust his decisions). The dies I'm using are Redding .308 comp dies, nothing fancy.
The fanciest part of the system are (1) the twist (9 or 8.7 or something fast like that) and (2) its on a long action, so it can load these long 198 way out and get lots of powder in there and still magazine feed.

best regards,
James

Thank you gentleman for your replies. I had imagined some special throating and dies. To hear that these work with a SAAMI reamer and standard dies is outstanding news to say the least!