Range Report 243 vs 6mm Rem

[Jedi]

Pert near set on 243 but have been told 6rem has that much more powder cap like 243 AI

More importantly longer neck, so may increase throat life etc

Since this will be 18" barrel extra fps is good

any comments? kinda threw a wrench in my plan

 

[oldgrayone]

Re: 243 vs 6mm Rem

Here ya go.

http://www.6mmbr.com/gunweek042.html

 

[kombayotch]

Re: 243 vs 6mm Rem

I've been loving the 6mm Crusader, which is a 6mm Rem. blown out. I'm finding that the longer neck gives better runouts, which is expected. However, with an 18" barrel, you aren't going to be able to take advantage of the greater case capacity. With the slower burning powders, you really need the barrel length to get a complete burn and get the fps up. In that barrel length, you're just wasting powder with the bigger cartridge.

I'd look at 6XC or 6x47 if you want the benefits of a longer neck and are really set on an 18" barrel. These will give you the same results for that barrel length.

 

[Jedi]

Re: 243 vs 6mm Rem

Hmmm
6x47 might be doable

not sure 6xc will match 243 numbers

243 still fav for now

good info thou

Rig will run suppressor 95% of time hence short barrel
Quick QL number crunch OAL 2.90 2900fps 27-28MOA @ 1k

 

[JRose]

Re: 243 vs 6mm Rem

What's your plan with it? 18" barrel on a .243 will
probably leave you disapointed if you are planning to throw the traditional DTACs...

 

[Jedi]

Re: 243 vs 6mm Rem

Dedicated suppressed rig

I will be running 105br bullet

Disappointed nah, initial QL info shows info stated above for baseline

This will shoot inside of LL 18" 260, ask him if he is disappointed

Lookin to be equal to my 308 performance 27MOA @ 1k, so thinking its very doable

Sticking with 243

 

[JRose]

Re: 243 vs 6mm Rem

Good luck with that. I think your 18" barreled .243 will fall flat on it's face. I'd like to know how it does when you get it done though.


Edit: if all your wanting to do is equal your performance of your .308 to 1k in terms of elevation needed to get there, you might be able to accomplish that. But what so you consider "equal"? Sure you get there in 27-30 MOA, but with a 105 gr pill. To me, a slow moving 105 grainer is useless.

 

[Jedi]

Re: 243 vs 6mm Rem

Yep just like Lowlites 18" 260 suk'd ass to, same thing just lil smaller bullet

Guess Lowlite dont know shit

Jeez Haters

 

[Jedi]

Re: 243 vs 6mm Rem

My bad
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1387882&page=1

read n heed
LONG is LAME

 

[JRose]

Re: 243 vs 6mm Rem

Brother I ain't hatin'... I'm just the dose of reality you choose to ignore trying to keep up with Franks new revelation. Seriously, he's shooting a .260, in an experimental rifle build, does not even have any velocities posted, and your ready to saw off all your barrels.

I'm 100% for you doing it. Prove me wrong, I'll eat crow.

 

[Jedi]

Re: 243 vs 6mm Rem

First Bro
I dont follow or attempt to emulate others

I had to be pointed to franks post i was unaware of it until then as i have not spent much time here lately.

Something i had considered for awhile now
my point being if a 260 worked then a 243 should also

Not new to this, i think there are enuff 18-20" 308 out there to prove that it works

Lastly this will always run suppressed, long barrels n suppressors just dont work.

I have nothing to prove to you, right or wrong

 

[JRose]

Re: 243 vs 6mm Rem

Yup, if it works for a .308, it'll work for all calibers.

 

[H5N1]

Re: 243 vs 6mm Rem

I run a .243 with 105's in a 26in BBL @3000fps, and that's all I can get safely in my rifle. I would consider a 7-08 in a shorter barrel, they should have a better chance than the 6mms because they are not necked down as much. If you do it please post your results.

 

[kombayotch]

Re: 243 vs 6mm Rem

Not hating... I have no doubt that, from the ballistics point of view, the shorter barrel will still perform in a respectable manner with any of those cartridges. However, if you don't have a good reason to go with a certain cartridge (standard cartridge like 308, factory match loads available, already shooting the caliber...), and you're going to be hand loading for it anyway, then I'd go for lower cost and/or efficiency.

What is the attraction to the 243 for this particular build anyway?

 

[Jedi]

Re: 243 vs 6mm Rem

243 easy to find, already have dies

meets fps goal and then some

Always wanted to run a can

Already have a dedicated f class 1k rig

Wots not to like.

I have been routinely told "ya cant do that"
47.8varget
x47 130 load that easy beats 260 loads
feeding 2.90 from mag
running 155 skinnies instead of 175smk back in 03

Now if your going to do this @ 2.800 ya might have problems but since i,m going to start @ 2.90 and work thru 2.970.

Barrel length is only a small part of equation and mostly effects FPS, followed by case cap

Focus on
105JLK .560bc @ 2900fps maybe more if i run 20" but then with can makes for 28" barrel...so 18" makes fps goal and keeps overall barrel to 26

 

[H5N1]

Re: 243 vs 6mm Rem

What FPS are you trying to get?

 

[Jedi]

Re: 243 vs 6mm Rem

2900 is goal

 

[Jedi]

Re: 243 vs 6mm Rem

Now this is all based on 18" barrel
as of yet i,m unable to determine effect of 8" of freebore.

It certainly will not detract from fps, but have no good info for figuring gains, thinking 30-50fps.

Yep i could just chop current 308 barrel
Wils little LTR ran same numbers as most do using 175smk.

Dont think of this as a dedicated 1k rig its not, sure it should be able to do it...but mostly sub 800yds

 

[H5N1]

Re: 243 vs 6mm Rem

2900 fps in .243 ,105 jlk with a 18in bbl?
I hope it works for you, cuz I hate to think I'm carrying 8in of barrel for 100fps.
Do it and post the results, I'd cut mine if I could do that.

 

[Jedi]

Re: 243 vs 6mm Rem

OAL thats wot its all about

if your not 2.90 or longer then your fps will suffer

Ck GEOS load on 6br, sure he had 10" more barrel but i will load longer and run a lighter bullet

And then there is the unknown of 8" of freebore for can

 

[Mike]

Re: 243 vs 6mm Rem

I, for one, can't wait to actually "see" the results of this. I have a hard time understanding why we here on the Hide who have shot 243 for years have been wasting our time with longer barrels.

It's not about what can be done, but what can be done consistently.

 

[donovan]

Re: 243 vs 6mm Rem

i think you can get there may have to lean on it , shit i dont know it will be close i think. i can get 3200[ leaning on it hard and doesnt like summertime temps...lol...] out of AI @ 24, and the new one is going to be 22. 105 amax moly'ed

 

[Jedi]

Re: 243 vs 6mm Rem

Same reason ya cant figure out how to run 47.8 vargay and 155

hell i could cheat a run 243wssm and make 2900 no sweat from a 18"...

Ref 260 18" build

why would a 243 not work

 

[DannySeesUSMC]

Re: 243 vs 6mm Rem

The JLK .243 105gr seems closer to .530 b.c. than .560 if you run it on JBM.

With an actual rifle length barrel a 95gr. Berger will have over 50" less drop at a 1000 yards and less drift than the 105 JLK at 2900fps...the 18" barrel would seem like you are taking away what is good about a 243...better ability to hit UKD targets.

Maybe a lighter contour 23" barrel...you can still be different but have better ballistics.

 

[Wild_Bill]

Re: 243 vs 6mm Rem

hi in that barrel i would go with a 6X47 Lapua a 243 with an 18" barrel makes a lot of muzzle blast and that is covered in you can but you will get more velocity from your rifle if it was in 6X47Lapua much better suited to the shorter barrel.

As for comparing a 260 to a 243 forget it you are in the next slower powders to make them work at the correct pressures and the expansion ratios of bore to case capacity are not the same it can be done but they are completly different you could compart a 6mmBR to a 260rem as they are a lot closer in expansion ratio's.

As you are building this up specificaly who cares if you have to buy another set of dies and cases set it up right at the start.

As this is a short barrel just going to a bigger case wont help as then you have to go to a slower powder that needs a longer barrel to achieve the extra potential velocity gain.
Put to much horsepower into it and you will just go slower.
If you have to use a 6mm the 6X47 Lapua is yout best option but in your case the 6.5X47 would possible be better with a 123 gr class projectile as the expansion ratio is better with a shorter barrel.

 

[7mmRM]

Re: 243 vs 6mm Rem

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mike</div><div class="ubbcode-body">I, for one, can't wait to actually "see" the results of this. I have a hard time understanding why we here on the Hide who have shot 243 for years have been wasting our time with longer barrels.

It's not about what can be done, but what can be done consistently. </div></div>

Bingo and then some......

 

[Jedi]

Re: 243 vs 6mm Rem

already run a 6.5x47 1k rig

still crunchin numbers etc

gotta look at 6xc

 

[HotIce]

Re: 243 vs 6mm Rem

Not for the ones running OAL-to-the-whazoo, but I really like the 6mm-AR idea as a semiauto solution.

 

[OKbow87]

Re: 243 vs 6mm Rem

Karl, I am very interested in your project and hope it goes well.

I have a 22" 6mm project that I am beginning right now. Gonna run the 105's. The only thing is I am undecided between 243 and 6X47. I'll be using seekins bottom metal that will allow me to run out to 2.94. I figured cheaper brass in the 243 and just use a faster powder, like varget, will make for similar velocity between the two. Only problem being not as much case fill in the 243. I was really hoping to get 2950+ out of the 22" barrel.

 

[Jedi]

Re: 243 vs 6mm Rem

Lets recap to avoid a pissing match

Dedicated suppressed rifle, hence short barrel
or swing a fishing pole

6mm, exact case undecided

Bullet as above, both pending meeting goal of 27-28MOA @ 1k

I,m not pulling data from my arse..QL doing numbers

BC numbers are whatever QL/QT have in data base or from maker.

Still crunching data
6-6.5x47 that interests me as i already run 6.5x47 so have dies on hand barring different neck bush

x47 brass is super strong and rated to 65k PSI and i do like it much...6-6.5x47 next on list

6xc has been suggested and will be looked at also

Sure i,m not going to beat a long barrel 6mm but thats not my goal, rather equal <span style="font-weight: bold">MY</span> 308 performance from 26"
27-28MOA @1k witnessed by many other members here.

Doable?? i think so

 

[Jedi]

Re: 243 vs 6mm Rem

OKBOW
from what i have learned so far 243 ya wanna use RL25

 

[JRose]

Re: 243 vs 6mm Rem

OKBOW,

RL25/H4350/RL17

 

[kombayotch]

Re: 243 vs 6mm Rem

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Karl2U</div><div class="ubbcode-body">
x47 brass is super strong and rated to 65k PSI and i do like it much...6-6.5x47 next on list

6xc has been suggested and will be looked at also
</div></div>

QL lists Pmax for the 6XC as 65kpsi also.

This also seems to confirm it has a Pmax close to the x47:
http://accurateshooter.wordpress.com/2007/09/15/mid-size-cartridge-comparison/

 

[MontanaMarine]

Re: 243 vs 6mm Rem

Karl2U, you might want to chat with member BgBmBoo. He can probably give you some good insights regarding velocity potential. He's running a Tikka T3 243 Win, cut to 16.xx".

 

[OKbow87]

Re: 243 vs 6mm Rem

Im running rl17 in my 7wsm for some scary good numbers right now. I would think 17 and 4350 would get much more of a complete burn over 4831sc, rl22/25, h1000 and some of the other popular powders for 105+ bullets in a longer barrel.

Sorry Karl im not trying to hijack your thread, just some info in here that should help the both of us.

 

[raptor99]

Re: 243 vs 6mm Rem

I think you may be a little optimistic with your numbers on a short barrel and the 243s.

You can run hotter loads but you will loose primer pockets. When I was doing load work ups for mine I ruined a bunch of brass.

I was using Winchester brass with H4350 and H1000 and a couple of VV powders. A little over 3000fps with 105s out of a 26" Kreiger was about as good as I could do without loosing primer pockets. I did get up to 3100fps+ but it was only one firing. Some other loads that were in the 3000fps range would only go 3 to 4 loadings and the brass was junk.

I had a 6XC and its not going to do what you want either. That is why I rechambered it to a 243 trying to get more velocity for shooting 115s but thats another story.

I wish you luck on your project and you will have to keep us posted on the results. I am affraid though that I have to agree with some of the other guys that you will need more barrel length to get the speed your looking for out of the 243s.

 

[Jedi]

Re: 243 vs 6mm Rem

Wrong powder bro

243 ya going to wanna run rl25 if going hot

IF ya run sub 2.900 OAL then that hurts also

QL does much, mostly identified for me powder which runs lowest PSI for FPS needed....RL25

since i,m gettin more active again on site i will go back to my old handle, might aviod some confusion for folks

 

[Jedi]

Re: 243 vs 6mm Rem

SO after much reading and numbers crunching
243 will do what i need, barrel life will be nominal 1-1.5k

6-6.5x47
luv the 6.5 i,m running, super strong brass, equal to or better than 260/6.5cm performance ....fact in my rifle shooting my loads.
expect 6-6.5x47 may very well be the same as 243 performance...hoping coz that would end this real quick

6mm rem
performs as needed can expect better barrel life.

6mm crusader i might even email GEO

right now pinning hopes on 6-6.5x47
i may have to run a 20" barrel, thats max lenght period

 

[Mike]

Re: 243 vs 6mm Rem

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jedi</div><div class="ubbcode-body">SO after much reading and numbers crunching
243 will do what i need, barrel life will be nominal 1-1.5k

</div></div>

I wouldn't count on that round count for the 243 to be accurate. Many who shoot the 243 here on the Hide have had accurate (sub moa) 243 rifles WELL past 1500 rounds. My 243 has >1K and is still sub .5moa. Just something to consider.

 

[JRose]

Re: 243 vs 6mm Rem

Also take into account the fact that you will be having to torch the throat on that thing to get near those velocities. That's going to diminish barrel life as well.

 

[Wild_Bill]

Re: 243 vs 6mm Rem

hi for what you want to do the only case you have stated to be suited is the 6X47 Lapua if you go to a larger case then you have to use a slower powder to gain the benifite of the case volume and then you need the longer barrel. Their are 15" pistols in 243 and the velocity realy suffers.

As an example would be 2 10" contenders one chambered for the 30-30 and the other for the 30 herret if loaded with the same projectiles the 30 herret with a case nearly 1/2" shorter will give you nearly 200fps more velocity and their is no way of getting the 30-30 to match it no matter what powders you use. the smaler cases are more suited to a shorter barrel and the 16-18" 6mm's are similar to the 10" 30 cals because of the expansion ratio of the bores.

So if you stick with the 6X47 Lapua you should be able to get 2800fps plus or minus and a bigger case will just make you use slower powder to get the advantage and then they will just create more blast and recoil without gaining more velocity you might even get less. I have also shot remington 600's with 16.5" barrels in 243 and they had a lot less velocity with a 90gr projectile than agter we rechambered it to 6mmbr with a break to keep the barrel length and the same projectiles with benchmark.


So with the 6X47 Lapua i would start with H4350 as the powder and if you have a lkong throat 40gr is possible but start at 38 and work up if you dont get the correct velocity then try Varget and whatever one gives you the best performance stick with it.

It is a mis understood thing that if you have a rifle cartrige like a 243 or 308 in a short barrel that a realy fast barrel will make the fastest velocity the cartrige will work best with a powder that is designed for the parent cartrige to burn with a medium to slow powder. TRhe powder that gives the highest velocity and best accuracy in a 26" barrel will usualy do the same in a 16" barrel it is just how the pressure curves work.

Hope this helps have a look at some data for metalic shilouete and they will help you with the things you need.

If you were to use a 223 Seekins mag system the best option off all would be a 6mmBR but the case is to short to run in a 308 mag.

 

[Wil]

Re: 243 vs 6mm Rem

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JRose</div><div class="ubbcode-body">Also take into account the fact that you will be having to torch the throat on that thing to get near those velocities. That's going to diminish barrel life as well. </div></div>


We both live right around the corner from Mark Pharr... We just stop in , chuck it up & set if back a bit...lol Easy fix.. <grin>

 

[Tyler Kemp]

Re: 243 vs 6mm Rem

You're gonna be leaning HARD on the brass to get those speeds in an 18" barrel.

 

[Jedi]

Re: 243 vs 6mm Rem

Done thinking about it
May have to run 20" but it will 6-6.5x47

Already have brass n dies 6.5x47...done deal

Perhaps
wife just said why not run x47????
WTF why didnt i think of that
I already have dies,brass, 2k bullets, several jugs 4350
and i know i can run 42.3 under i 130jlk with zero issues.
In fact 4350 will fill case before you hit pressure probs

Damn i made that way to hard

Fact i can beat 260/CM performance no issue, ck reloading section if ya doubt me

My load 41.5 4350 130jlk 2975fps 28"
read em weep
thnx for all ideas
18" x47 it is

 

[Jedi]

Re: 243 vs 6mm Rem

Finale build info
6.5x47 20" 2850fps 130vld
QL/QT 26.5 MOA @ 1k 200yd zero

Thats pert good meets performance needs althou i had to go 20" on barrel no biggie

Cant wait to get this done and get some real world data

Big thnx to Nez and Microsuck, QL and suppressor.

 

[858]

Re: 243 vs 6mm Rem

I'm currently working up a 20" 243 Win and based on my limited experience you will be on the ragged edge at 2900fps. My initial goal was 3000fps but its not realistic. 2800-2900 fps will be pretty warm, 2900fps with 105VLD will easily own a 308 to 1000 yards and beyond.

I had 4831SC on hand but QL shows its probably too slow, as advised previously, H4350 should get you closer. I intend to shoot my ladder and then make the switch to 4350 assuming accuracy holds.

My rifle is also to be suppressor dedicated.

 

[aqualung]

Re: 243 vs 6mm Rem

Hi Guys,

I'm running a 20" .243Win in a rem 700 and it's a dedicated suppressed rifle. Currently running 90grn Nosler BT's with 36.4grn RL15 ahead of federal GMM LR primers.

Accuracy is outstanding at the short ranges I use it at (300yds and in), but I'm a little confused.

My barrel OAL runs at 24" or so. Don't you guys have reflex type moderators?

Check out UK Custom shop or Wilcat moderators (same people, different products). Don't have the url handy, but I can find it for you if you want it.

8" of suppressor/moderator hanging off the end of your barrel seems like a lot. The reflex type of suppressor is very popular in Europe, with the expansion chamber sleeved over the barrel, you only get the baffle stack in front of the muzzle. This makes it a lot more compact and improves the balance/handling.

I've probably rambled a bit, as I'm knackered, but it's just a thought. Hope it helps.

Neil