Can I Stay supersonic at 1000 yards??

[mrbeer]

I have a accurized rem 700 in .308 with a 20 inch Krieger barrel with a 1:10 twist in a McMillan A5. I would like to shoot this rifle out to 1000 yards at some tactical competitions at my local club, but I fear with a 20 inch barrel that this may be unrealistic. My questions are as follows.

1. Do you believe I can formulate a load to keep a bullet supersonic out to 1000 yards with a 20 inch barrel, or am I trying to turn a ford f-150 into a Ferrari?

2. If you believe I can, where would you start (Load Data). I was thinking of using hot loaded berger 155.5's or 175 SMK's. Would a slightly faster burning powder be a better choice to get complete burn out of a 20 inch barrel. I am new to reloading and have little experience with differences between powders.

If all else fails, I may just sell the rifle and build a REAL f-class rifle

Any input you have would be greatly appreciated!

Thanks.

 

[blawton]

With hot handloads it shouldn't be a problem. It depends on what type of f-class you want to shoot. The open class is gonna be a lot tougher to compete in when you get into it. Running 190 grain bergers should be the ticket with a powder like rl-17 should work fine even in a 20 inch barrel. A 208 a max or 210 might work as well. Remember the faster the bullets go the faster they slow down. Running a higher bc bullet will help you more if you barrel twist is right for them. Nitriding helps alot. We were pushing the 208's at 2700 fps out of a 20" barrel that was done. IIRC the load was 52 grains of 17 but they run a lot lower pressure with the nitriding.

 

[bozo699]

I have a friend with a factory savage 20" tactical rifle that regulary hits my 1081 yd gong w/factory 168 smk in federal gold metal match ammo. I don't know if it is still super or subsonic but the groups are impressive.
Wayne.

 

[mrbeer]

What exactly is nitriding.... it is a process on the barrel or the bullets?

 

[FilippoMo]

It is a form surface hardening of the bore of the barrels.There are different processes that go by the collective name of nitriding
I have pm Notaguru for details.
sincerely
Filippo

 

[Laurie]

Mrbeer,

you'll have real trouble producing any load for a 20" barrel .308W that is both accurate and remains supersonic at this distance. You simply won't be competitive in F-TR, but tactical may be very different given the nature of the rifles that are used - you'll know better than me on this matter, not being a tactical competitor myself.

You have two choices:

(1) depending on the competition rules re allowed calibres and cartridges, rebarrel to something that is ballistically more efficient. In Europe that usually means .260 Rem or 6.5X47 Lapua, if you're in North America maybe 6.5mm Hornady Creedmoor which isn't widely seen here. Even so, you'd also benefit from a few more inches of barrel, going up to 24".

(2) Stick to your present set-up and work up a load with a bullet that isn't too bothered by transonic and subsonic velocities using as heavy a load as retains good accuracy. The long-boattail Sierra MKs - 190, 200, and 220 gn weight - have a very good reputation here. They were long popular with Match Rifle shooters who shoot .308W at 1,100 and 1,200yd in the UK and Canada, up to 1,500yd in Australia. With your barrel length, the 190 would seem the best bet. The recently introduced Berger 185gn BT Long-Range (NOT the VLD) has quickly acquired a great reputation in F-TR and Fullbore/Palma (in US regulations matches that don't limit the shooter to bullets 'of less than 156gn weight') for 1,000yd shooting and has also been used by some MR shooters. I don't know how it would cope with lower MVs and subsonic flight (2,800 fps from a 30" barrel rifle sees it still at over 1,400 fps at 1,000yd), but it's a very efficient design and would probably do just fine in this role too.

Avoid short-range match bullets with steep (above 10-degrees) boat-tail angles as they produce turbulence and increased drag as they enter transonic flight and usually become unstable as a result. This category includes the 168gn Sierra MK, Nosler Custom Competition, Hornady HPBT Match, Speer Gold Match, all Hornady A-Max bullets in all weights apart from the 208gn which is a true long-range VLD, and the Sierra 180gn MK.

Many will tell you to use the 175gn Sierra MK, it being used in the M118LR military sniper round loaded to a modest 2,590 fps nominal from a 24" barrel M24 or similar. It will hit the target at 1,000yd, but accuracy suffers appreciably beyond 800 metres. The 190 Sierra is a better bet at modest MVs.

If you want to look into the whole issue of long-range ballistics for accurate shooting, the best thing you can do is get a copy of Bryan Litz's book "Applied Ballistics For Long Range Shooting" a detailed but equation-less description of how ballistics work for rifle shooters with a detailed evaluation of around 175 bullets in .224 to .338 calibres that are suitable for longer range hunting and target shooting, this based on 1,000yd tests. Bryan was an independent ballistics consultant when he did this work and wrote the book, but has since moved to California as Berger Bullets in-house ballistician. If interested look at his Applied Ballistics website:

http://appliedballisticsllc.com/


which several interesting articles on it as well as details of and an order system for his book in the 'products' section.

Another thing having a look at is:

http://www.bergerbullets.com/Cartridges/30%20Cal/308%20Win/308%20Win%20-%20Target.html

on bullet selection for .308W for long-range shooting including application to 'service rifles' whose shorter barrels and limitations make them similar to your situation.

The Snipers Hide forum has a lot of useful stuff for your situation:

http://www.snipershide.com/forum/ubbthreads.php?ubb=cfrm

as does Sniper Central:

http://www.snipercentral.com/forums/

I hope these pointers help a little and good shooting.

Laurie,
York, England

 

[JRS]

Very well written Laurie!

Your thoughts on the LAPUA SCENAR 185?

 

[Laurie]

Your thoughts on the LAPUA SCENAR 185?

It's an excellent shorter range bullet. I used to think it was a long-range number given its weight, Lapua claiming a G1 BC somewhere around 0.520, and the reputation of its 155gn stablemate. However, Bryan Litz's experiments produced an average long-range G7 BC of 0.247, G1 0.483 which is only marginally better than the 175gn Sierra MK. (That compares to BL's results of 0.287/0.560 for the Berger 185gn BT L-R and 0.270/0.527 for the 190gn SMK, exactly in line with what Sierra claims for the bullet.) If you look at the 185gn Scenar it has a short and blunt nose section in comparison to virtually all other match bullets.

So, I wouldn't recommend it for 1,000yd shooting - it makes a very good 200-600yd number in a barrel that likes it.

One thing I remembered after finishing my last post on mrbeer's question was that a shooting friend in the north of England who does very well indeed in top club-level F-Class with a 20" tactical .260 Rem, had rebarrelled this piece from .308W, also in 20" barrel form and with a fast 1-10" twist rate. He belted 155gn Scenars out fast enough to do very well in 1,000yd competitions even though this combination broke all the ballistics rules. It helped that he's a very good shot, of course.

A lot comes down to whether the rifle will take hot loads as you really have to load any bullet up for this range out of this barrel length. I had a 24" barrel .308W FN Special Police Rifle that I used in F-TR a couple of years ago. It wouldn't group with hot loads so I couldn't get 155s out at much more than 2,750 fps without exceeding a miserable 1-MOA. It did work at long ranges with the 190gn Sierra MK though over a heavy load of Viht N550 giving around 2,650 fps and half-MOA precision. My firing point neighbours complained about its muzzle blast!

Laurie,
York, England

 

[JRS]

Thank you sir!

 

[mrbeer]

Laurie,

Thank you very much for all of your information. I will read up on everything you suggested. I love to get my hands on anything technical.

I received the following load information from someone at the snipercentral forum.
______________________________________
155 Scenar (or 155.5 Berger FullBore)
47.8 gr Varget (47.4 in Laupa cases)
Win cases
CCI primers
2.943 OAL (still compressed)

In a 24" tube will reach 1300 yards at Mach.
In a 20" tube will reach 1200 yards at Mach.
_______________________________________

I may try something close to these loads, but I am worried about accuracy and any degree of consistency with the hot loads that 155's will require. I will also take your suggestion and make up some loads with 185-190+ grain bullets not VLD's and start to test them.

Also, I want to build an "all around rifle" that I can shoot in long range Benchrest, F-Class, and Tactical competitions. I was thinking of a 17 pound rifle in a no-neck turn 6BR with a 28inch barrel with a "hybridized" benchrest / F-Class stock. What are your thoughts? I just cant avoid all the good things I hear about 6BR no matter how hard I try. I originally was looking at .243 win or .243 AI, but despite its "superior ballistics" on paper, the general bendchrest population seems to think that you can get more consistent and accurate loads minimizing ES out of 6BR.

Any input you have would be helpful.

Thanks!

~Mr. Beer (PS. nothing beats a refreshing English mild beer after a day at the shooting range)

 

[Laurie]

I'd be most dubious about these supersonic to wherever figures. Even on Sierra Infinity V.6 that uses inaccurate G1 drag-curve BCs, the 155gn Lapua Scenar at the 3,000 fps MV you could expect from this loading in a 30" tight-bore barrel target rifle is only barely supersonic at 1,300, and it takes over 2,800 fps MV to repeat the trick at 1,200, although that might just be possible in a 20" barrel rifle at way above safe pressures.

Or then again, these sniper types like shooting 10,000 ft ASL in 100-degree heat in deserts, so who knows?

However, run the best of the the 0.308" 155s at 3,000 fps using Bryan Litz's experimentally obtained G7 BC value through an appropriate ballistics program and you get rather different results - 1,151, 1,059, and 1,010 retained velocities at 1,100, 1,200 and 1,300 yards under standard ballistics environmental conditions. (59F etc).

Your triple role 6BR 17lb rifle sounds eminently sensible. I can say that hand on heart as Walker Rifles has just built same for me but in 6XC, albeit only for the F-Class and BR LG roles in single-shot form. What you will likely find is that it takes a fair degree of paring to make the 17lb Light Gun weight limit with a modified F-Class stock. My gunsmith had to ask the UK McMillan importer to specify as low a weight as the company could sensibly produce for what started as a McMillan F-Class type. The cheekpiece has been moulded into the buttstock too removing the height adjustment bits. Even at that, I'm restricted to a 1" dia fixed power scope to keep weight down. (This is with the relatively heavy Barnard action that weighs around 3lb.)

Alternatively, there is the McRees MOD-MPSS aluminium allloy modular stock system where you can add, remove and swap bits for the different roles. I've done this with my Savage 12 action F-TR rifle using a 3" wide BR forend off the bench and a 2.5" wide varmint forend and bipod for F-TR. There is a tactical forend too. McRees Precision won't export them to Europe now unfortunately, but there is a Spanish version and that is being put into production in the UK shortly too getting around that problem, but we have to see if it will be available for the large number of actions that the US maker caters for. Also, it's a rather heavy bit of kit. (If you're interested in this stock system, see the August and September issues of the free UK based online TargetShooter magazine -

http://www.targetshooter.co.uk/

which has a two-issue write-up of my .223 F-TR rifle using it. September goes live on Thursday.)

For F-Open, the limit rises to 22lb, so you can take the lightweight scope off the rifle in its BR guise and mount a heavier and larger objective lens variable model not worrying about the extra pound or pound a half. So, you want a QD scope mount system - M1913 Picatinny or similar rail and lever mounts or similar.

You'll need a rail inletted into the forend as well for the tactical role to mount a bipod unless you have a mounting spigot for a Versa-Pod type moulded into the front surface of the forend (but I think that in keeping weight down, the forend may end up overly shallow for this solution). A rail adds a little weight and detracts from the rifle's performance on the front-rest.

The only other issue I can think of is getting the 6BR to feed reliably for the tactical role. 6XC or 6.5X47L, or its necked-down 6X47L wildcat will be simpler. It's not impossible to get the 6BR to feed from a 'standard design' detachable box mag. Here in the UK, Dave Wylde in South Yorkshire Shooting Supplies has built several such rifles now. I don't know which magazine is employed, but most likely the Accuracy International model, and knowing Dave's work probably on Surgeon actions.

Laurie,
York, England

 

[blawton]

What exactly is nitriding.... it is a process on the barrel or the bullets?

Black Nitriding, or Ferritic Nitrocarburizing, is the thermochemical that simultaneously diffuses nitrogen and carbon into the surface of ferrous metals. During the process, a two-part surface layer is formed, an outer iron nitride layer with a nitrogen diffusion layer below it. During this treatment, nitrogen and carbon are absorbed by and diffused into the surface of the metal. Reproducible and uniform layers with a predetermined thickness will be formed on all areas of the metal. The result of this process is markedly improved surface properties on ferrous metal parts while maintaining dimensional and shape stability.

Metal components treated with the Black Nitriding have increased wear-resistance, fatigue strength, corrosion resistance, lubricity and cosmetic appeal. Often replacing the more expensive processes of hard chrome or nickel plating, Salt Bath Nitriding gives better corrosion protection at equivalent or lower costs. Additionally, Salt Bath Nitriding is commonly used as an alternative to high temperature conventional heat treatments such as carburizing and carbonitriding.

 

[1000yardstare]

No way I can keep up to Laurie and NotaGuru in technical offerings.

I will approach the question from a more practical angle. I try to alternate RSO and shooter in different F Class practises. I am in the butts sometimes pulling target boards and marking during a 1000 yard practise.

This past July, a chap showed up with a Rem SPS Varmint, 26 inch barrel, and some 150 gr PSP Winchester .308 Super X hunting ammo. Had a first hand experience with bullets coming in subsonic. Took a few shots to figure out what was going on.

The first one sounded like a WWII V1 DoodleBug. Must have been tumbling end-over-end. I think it went over the backstop but it is a huge Army base and the safety template allows for .50 BMG. The second shot hit the earth in front of the butts and sprayed dirt on my target. The shooter was actually aiming at the target 2 positions to my right. The third shot came in like a Roger Clemens curve ball and hit the backstop 2 positions to my left. You could hear it curving through the air.

About then we phoned back to the RSO and said "Pull that ammo off the line!!".

So please, whatever load you finally decide on, think of the pullers in the butts and keep it supersonic.

 

[mrbeer]

Thanks again for the excellent information.

I read several articles on appliedballistics.com. The articles were very informative and give me an idea of how I will go about building my all purpose rifle. I also contacted the folks at McRees Precision. I am highly interested in their solution and will obtain more information from them in the coming weeks. My largest concern with the McRees MOD MPSS is its union with the action. The "stock" is not bedded to the action in what we would consider the traditional way. I need to better understand their method for securing the action to their stock and how this translates to real world accuracy.

I have another question for you. This may appear simple but I am just learning...

I often see BR shooters refer to their "ES" which I assume to mean "extreme spread." Is this term usually used to refer to spread in projectile velocity or in group size? Shooters are always trying to reduce their ES.

What are your thoughts.

Thanks.

I may post this as a general topic in the forums to see what responses I get...ill bet ill get different answers.

 

[mrbeer]

No way I can keep up to Laurie and NotaGuru in technical offerings.

I will approach the question from a more practical angle. I try to alternate RSO and shooter in different F Class practises. I am in the butts sometimes pulling target boards and marking during a 1000 yard practise.

This past July, a chap showed up with a Rem SPS Varmint, 26 inch barrel, and some 150 gr PSP Winchester .308 Super X hunting ammo. Had a first hand experience with bullets coming in subsonic. Took a few shots to figure out what was going on.

The first one sounded like a WWII V1 DoodleBug. Must have been tumbling end-over-end. I think it actually went over the backstop but it is a huge Army base and the safety template allows for .50 BMG. The second shot hit the earth in front of the butts and sprayed dirt on my target. The shooter was actually aiming at the target 2 positions to my right. The third shot came in like a Roger Clemens curve ball and hit the backstop 2 positions to my left. You could hear it curving through the air.

About then we phoned back to the RSO and said "Pull that ammo off the line!!".

So please, whatever load you finally decide on, think of the pullers in the butts and keep it supersonic.

Its funny that you mention this! I just spent my first weekend in the pits pulling targets for 1000 yard practice. It was great, BUT I got showered with dirt from a few short shots. It was quite unnerving to think that I had bullets whizzing bye only 1-3 feet above my head.

Get this....I shot for the first time to any distance over 100 yards with my .308. I first shot at 600 yards. My very first shot...clicked in off of a ballistics chart printed an hour earlier, was in the 10 ring....how luck is that???

I was shooting fed GMM 175SMK factory ammo. I later went out to 1000 yards and once I got on paper, the rifle was able to keep it on the target every time after that.... but I imagine it was still going subsonic. I was shooting next to some f-class shooters who both were shooting 6BR's. I immediately became disenchanted with my rifle as I saw them put round after round in the 9 and 10 ring with half the recoil from 1000 yards. One guy let me shoot his 6BR. After 5 rounds I was HOOKED. I now have to build a new rifle.

 

[cfvickers]

Don't know if it works on a .308 but I have a 6.5x55 with a 20 inch barrel, and I can get very close to book velocities measured on a 24 inch barrel by using a hot primer like fed 215. I probably sound like a broken record saying this but It is the greatest thing I have come across yet as far as getting the most out of that short barrel.

 

[Laurie]

mrbeer,

My largest concern with the McRees MOD MPSS is its union with the action. The "stock" is not bedded to the action in what we would consider the traditional way. I need to better understand their method for securing the action to their stock and how this translates to real world accuracy.

No-bedding aluminium alloy chassis or tubeguns stocks are quite amazing animals. Google MAK and Competitive Shooting Stuff or Gary Eliseo ...... alternatively look through Gun of the Week on the main site for features on tubeguns using stocks from this pair ...... alternatively look at the Daily Bulletin associated with the main site for the August 28 entry about some amazing groups using a 6mm BR CSS R5 tactical repeater rifle. (This isn't the first time that 6mmBR / AccurateShooter has reported fantastic results from Gary Eliseo's R5 and other models.)

I should have mentioned the CSS / Eliseo tubegun alongside the McRees system as it's another very flexible and effective multi-purpose platform, although its starting point is target shooting while the McRees is tactical and military. As with the McRees and the Tubb T2K systems, it is another 'straight-line' layout design that puts the recoil mostly straight back into the shoulder without a turning motion.

You couldn't have done what these systems do not all that many years ago. The difference is CNC machining that turns out very accurately made components that are (a) 'true', and (b) consistent from lot to lot to lot. That must apply to both stock and action, and there's the rub. Certain mass-produced actions made with pre-CNC manufacturing methods do not necessarily provide the necessary 'trueness' or consistency, in fact some are notorious for not doing so. Therefore they either need a conventional bedding system that starts soft and adapts to the receiver contours before hardening into an exact mirror image of the bedding area of the action, or as in the single shot version of the CSS tubegun stock designed for the Remington 700 action uses a method that finds another way around, in this case a large circular recoil lug that locates the action in the stock and does much of the bearing work; alternatively, as in the MAK system, glueing Remy actions into the main tube section, the glue being in effect bedding.

Nearly all custom actions including the many now on the market that use the Remington 700 external 'footprint' such as those from Surgeon, Stiller and the Barnard Model S and Model SM (magazine) are very precisely made, as are some factory actions notably from Savage. So the McRees system works very well with the Savage 12 action for instance - you know it is going to be an excellent fit, basically because every individual centre stock section made for that action, and every indidvidual Savage receiver are identical to every other, so if the prototypes produce perfect fits, so does every subsequent pairing of production items. With both components being very strong and rigid too, the action screws are done up very tightly which helps and there are no worries about distorting components as in some conventionally stocked setups.

I often see BR shooters refer to their "ES" which I assume to mean "extreme spread." Is this term usually used to refer to spread in projectile velocity or in group size? Shooters are always trying to reduce their ES.

This is spread in muzzle velocities as you deduce. The reasons for such being there in the first place are manifold, some arising from the original cartridge design, many from cartridge component suitability, component quality / consistency, handloading practices etc. One might assume that if a batch of ammo produced a small or even nil spread (which you never get) it would produce small groups, but it often doesn't. This isn't much of an issue for short-range shooters where precision is the goal - the much vaunted PPCs used in 100 and 200yd BR shooting produce tiny groups, but their ammunition may also produce substantial spreads. Where it is significant is at long ranges as MV variations should produce different elevation strikes on the target all other things being equal. So 1,000yd shooters look for three things - 'precision' (small groups); high enough MVs and a suitably efficient bullet to (a) remain comfortably supersonic at the target end of the flight and (b) minimise wind drift; finally, small ES values to keep 'verticals' small.

1,000yd shooters look for ES values under 20 fps from a 10-round string. It's particularly crucial for .308 Win users because of this cartridge's marginal suitability for this distance and there is much discussion on the US Rifle Teams' Long-Range Shooting forum on this subject, especially over the recently introduced small primer and flash-hole Lapua 'Palma' 308 brass developed for this very reason - to reduce ES.

Have a look at this forum, especially the Precision Handloading and External Ballistics sections if you're likely to continue with .308W at long ranges. There is lots of good stuff here.

http://www.usrifleteams.com/lrforum/

I won't say more on causes and effects as this is a many times aired subject on this forum. Do a search and you'll find several recent threads on it.

Laurie

 

[blawton]

Laurie,
You should take a look at these as well. www.xlrindustries.com.

 

[Laurie]

Notaguru,

Laurie,
You should take a look at these as well. www.xlrindustries.com.

Wow! This design makes the McRees look over-specified! Thanks for the link - I'll pass it around to some people who will be interested.

However, it's most unlikely we'll ever see any over here unless the US State Department eases it export regulations on firearms components and crucially, reduces its export licence fees which now make export of a single component, or small number of components, ruinously expensive, as well as a bureaucratic nightmare. Getting the necessary paperwork done and cleared can take months at times too. This policy, (alongside a feeling that we're regarded as 'untrustworthy' by the US State Department and Department of Homeland Security), has caused a lot of grief.

The good news is that we're increasingly seeing home-designed and manufactured actions appear, stocks now on the way too, to replace US made items. We've also found sources for many formerly American supplied items in other parts of the world, countries whose authorities are keen to encourage exports even for gun parts.

American leaders need to beware of doing what our forebears in Britain did when we had an empire that was in effect a huge and largely closed 'home market' for everything from cheap metal trinkets, simple steel fastenings etc up to railway rolling stock, ships and motor vehicles. Small customers, specialist goods, and customer service were seen as unimportant and other (political) issues often took precedence over trade. Then one day, we woke up and found most of the British manufacturing industry was closing down for lack of orders, because there's no such thing as a guranteed market, and every little order matters in the long run.

On that cheerful note, thanks again,

Laurie,
York, England

 

[1000yardstare]

Laurie.
I am curious about the cost of the Export Permits going into the U.K. from the U.S. State Dept.

I have gone from Ontario across the U.S. border to a gun shop in New York State and bought rifles and shotguns. The cost of the Export Permit is $100 U.S dollars in each case but the gun shop readily admits the Export Permit is free from the State Dept. The $100 is actually the gun shop`s fee for handling the process which I can`t imagine is very expensive - sending a fax, receiving a fax and driving the gun to Canada Customs at the border, a 20 minute drive.

But maybe the State Dept is charging a fee to send an Export Permit off the North American Continent? I admit to having no knowledge of this. Anyway, hope you aren`t being ripped off by gun shops on your side of the pond.

Bill