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SwissReloaderRS52 / Quickload


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Hi all. I'm brand new to this site so forgive me if I screw up!!

I am a Target Rifle shooter, so operate from 300 - 1100 yard ranges. I have been trying for some time to get my bullets (Sierra MK Palma 2156) up near the 3000fps mark but get to high pressures at about 2900fps using Vit N140. I'm using a nearly new 32'' Border barrel, 1:12 twist. with the bullet 20 thou off the lands (coal 2.905''). The Quickload programme says 45.6 grn of N140 will get me to 2919fps with a pressure of just under 55 thousand psi. More than that and the pressures climb pretty high.

Then I discovered SwissReloader RS52 powder! Quikload indicates a 48.9 grn load of RS52 will get me up to 3,002 fps but with a chamber pressure of only 52,355 psi - does this sound right?? Does anyone have any reloading experience with this powder? if so, let me know if it's as good as it sounds as I'd also like to try it for heavier pellets too, 175's maybe.

Cheers & sorry to ramble on a bit.

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You'll find a lot of .308 shooters are switching over to RS 52 because we get higher velocities at lower pressures than with most other powders.

Using Lapua Palma brass, I've found the sweet spot with my rifle, which is a 32" Benchmark 10 twist barrel, is 48.0 grains of RS 52 with the Berger 155.5 grain bullet seated 0.020" off the lands at 2.940" COAL. This load chronographs at 3100 fps, both on my own Chrony F1 and a friend Magnetospeed.. I have seen no pressure signs with this load; no tight bolt lift, no cratered primers etc. I've also used this load with standard Lapua brass and not observed loose primers etc.

 

QuickLoad with the RS plug-in says that the MV for my above load is 2960 fps so there is a discrepancy there. I have also found differences between observed an RS data for RS50 (TR 140), so I have misgivings about the accuracy of the plug-in. However. the QL chamber pressure predictions for the two powders mentioned are very low compared to other powders and even if these are wrong I can't imagine it being so wrong as to take it into the danger levels.

 

HTH

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First things first. when you say 'high pressures' from N140 much above 2,900 fps, do you mean actual high pressure (hard bolt lift and extraction, cratered / very flat primers, short case life due to primer pocket / case-head enlargement)? Or do you mean, you've looked at QuickLOAD and become frightened at the thought of pressure above 55,000 psi?

 

308 Win is a 60,000 psi cartridge and often performs best not too much below that level. 55,000 psi is a mild and for an 1,100 yard competitor, extremely limiting ceiling. N140 will give you what you want, that is MVs ~3,000 fps from the new model 155 Palma SMK given your relatively long throating and 32-inch barrel length. People have been running at 2,950 fps and more for many years with this powder.

 

You don't say what brass you're using, also whether you've measured the 'overflow water capacity' from a fired unsized case and used it in QL - it can make a difference to the outputs, but RWS and Lapua cases are usually around the QL default at 56.0gn H2O when fired in a 'tightish' match chamber. Norma is larger capacity and Winchester larger still, which reduces pressures / velocities and therefore need slightly higher charges.

 

So far as Reload Swiss RS propellants go, there are three good alternatives for your application. RS40 is a high-energy (infused nitroglycerine) relatively fast burner, really a 5.56/223 mid bullet weight number, but works VERY well with 3,000 + fps MVs available in 308 match rifles, but only with 155s. With anything heavier, you run into pressure problems before achieving full velocity.

 

RS50, already widely known as TR140, is a single-base type that does anything N140 will do and likely a little more due to Nitrochemie's advanced infused throughout the grain deterrents technology that controls the burn for longer than conventionally applied surface coatings. Like N140, it'll happily give you 3,000 fps and more with your set-up.

 

Thirdly, RS52 which like RS40 is a high-energy number, but is slower burning and very closely matches charge weights that work well with H. VarGet and Alliant Re15, but usually produces somewhat higher (~40 fps) MVs for same loads over this pair. It can be used happily with 155s, but also heavier bullets - I've run up to 190s with it and I hear of it having been used with 210s successfully, but have no details.

 

Your QL derived charge weight seems too high from my experience with a very similar set-up to yours, and the MVs far too low. That also makes me wonder about the PMax value. I ran the powder up to 47.0gn with the #2156 SMK and Berger 155.5gn Target BT Fullbore and was achieving >3,050 fps at this weight, but MV spreads were larger than loads in the mid 46s and I suspect this may be where it's happiest, but it'll depend on the rifle. In good brass and a good rifle with CCI-BR2 or F210M primers, it should produce ES values in high single or low double figures. Lapua Palma small primer brass will reduce that further, but generally need an extra 0.5gn charge weight to compensate for the reduced ignition energy.

 

Incidentally, unless you're already getting tiny groups with the 2156, I'd suggest experimenting with a bit deeper seating - this bullet often needs a 30 or even 40 thou' jump to perform.

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Thanks for the feedback fella's. Laurie, I should have mentioned the cases & primers in the original piece, I do use RWS once fired cases & CCI BR2 primers. As for the pressures, I think I was a bit wary of getting up towards the 55 - 56,000 psi area but, from your comments, it seems I was slightly wrong about that and maybe headed a bit higher than those figures.

I have not had any real problems with stuck cases or heavy bolt lift. One last thing, I'll give the slightly deeper seating a go in future - 30 / 40 thou as suggested.

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One other point, I should have asked / mentioned. Do you know whether your gunsmith used a 'tight' barrel blank or a SAAMI standard? Although we're well out of the days of using RG 7.62mm, many gunsmiths who build TR rifles still use a slightly tight bore barrel to get MVs up to the magic 2,950 with 155s. (The NRA RWS ammo is loaded to suit such barrels, and it can give disappointing velocities with a standard dimension barrel - I have a Howa 1500 that won't reach 2,600 fps with this ammo although it actually groups very well in it.)

 

SAAMI is 0.300" bore dia. and 0.3080" groove dia, but many TR barrels are specced at ~0.298/0.3075-3078". This puts pressure and velocities up considerably and should be taken into account when using QuickLOAD as it can understate pressures if on the default settings. Hence the importance of a chronograph alongside QL - to see what's actually happening as opposed to what the model computes, excellent though it is.

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  • 1 month later...

Any delayed combustion issues with RS52?

Do I need using magnum primers?

 

After QL simulation, just arranged some loads for testing pressures and MVs.

185 Jug

Lapua Palma brass

Powder weights from 46.5 to 48.5

COAL 2.940"

 

Cheers

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For what it's worth, I've been playing with RS 52 for a while now with 77's in .223 and getting around 2740 with an 18" barrel with no signs of pressure

I have quickload but don't think it will work on a Mac

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For what it's worth, I've been playing with RS 52 for a while now with 77's in .223 and getting around 2740 with an 18" barrel with no signs of pressure

I have quickload but don't think it will work on a Mac

I use a Mac as well and run QL on it.

Install VirtualBox in order to virtualize a Windows machine. Install QL. That's all

QL will run faster and better

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Please note that although my starting point was below the recommended maximum load indicated on the RS data page, the following load may not be safe in your rifle.

 

I've recently tried RS52 in 308 using 2155's seated 0.020" off the lands, once fired RWS (ex NRA) and Rem 9.5 primers.............3.03 gms/46.9 grains made 3000 fps.

The same weight of TR140 made 2908. .

Barrel is a 30" Bartlein 11 twist. It's a Palma profile but I'm not sure if the bore is "tight".

 

The rifle felt noticeably different to shoot........difficult to describe, but maybe less recoil and a different sound, not the usual sharp "bark" of N140 or TR140.

This was the first sequence of one offs with this powder loaded from 3.03 to 3.11 gms (my balance is ex-Laboratory) in 0.02 gm steps.

 

Chrony was a Magnetospeed.

 


H/man

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Hi Hauptman.

What you're describing here is pretty near my set up. My barrel is a bit longer (+2 ins) and my twist is a bit slower ( 1:12) but my bore is tight at .298 ins. I'm using the 155 Sierra Palma 2156 with the better B.C. So, once I've been to the show next month & got some RS52 it'll be off to Bisley to see how it goes! One thing though, does anyone have any ideas regarding barrel wear using this powder?

As its a slightly hotter burn + increased velocities etc. I'd be interested to hear....

Gotta get me one of them Magnetospeed's too.

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Very good question!

 

Is it an "improved" single base, or a semi double base, or what?

RS says it is a single base powder with a nytroglicerine coating. So what? Will my throat suffer?

Cheers

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RS52 is a 'high-energy' propellant, as are the Viht N500 series, all Bofors manufactured Alliant 'Reloder' series powders and a fair few more. That is, you make a nitrocellulose (single-base) propellant and at a late stage of the manufacturing process, infuse a certain amount of nitroglycerine using various patented processes. This does two things, it increases the weight at the molecular level so that you get more grains weight of kernels into a space limited case and more weight = more energy; it increases the specific energy so that a given charge weight contains more energy and produces a higher MV. For instance, Viht N140 has an SE rating of 3,720 KJ / Kg (where J = Joules energy) and its high energy treated derivative has 4,100 KJ / Kg, an increase of 10.2%. With a typical rifle cartridge thermal efficiency rating of ~35%, that means an N540 charge will produce around 3.6% greater ME in ft/lbs or whatever - all other things being the same. Typically, high-energy powders allow heavier charges too, so that further increases available MVs and MEs.

 

True double-base powders have NG combined with NC at a very early stage of producing the propellant in its plasticised form before turning it into stick, balls, rods of whatever and drying the solvents out. Alfred Nobel's 'Ballistite' was the first double-base propellant in which NG was added to the base guncotton and used to plasticise it. The British governmment's 'Cordite' was very similar - so similar that Nobel took HMG to court for patent infringement but failed in his action. Today, such d-b powders are rare in smallarms uses, nearly all extruded NG types being 'high-energy', that is the NG added to nearly finished conventional s-b kernels. However, all 'ball' powders are double-based, so buy any Ramshot, Accurate, Hodgdon 'Spherical', Winchester 'ball' and you get N-G for your money, sometimes a lot. Likewise flake type or flattened ball pistol and shotgun powders (even more in these cases).

 

So, do pistols burn barrels out in 1,000 rounds because they use Alliant Bullseye with huge % amounts of N-G, maybe three or four times what's in RS52 in component % terms? Not usually - they last 'forever' - but they may be running at 10,000 psi and your 308 Win could see 60,000 psi. Throw in Nitrochemie's secret IE through the mix deterrent infusion process which controls the burn rate for much longer than propellants with traditional surface coatings

 

http://bulletin.accurateshooter.com/2012/01/shot-show-new-reloder-33-and-power-pro-1000-from-alliant/

 

and you can raise MVs substantially within allowed pressures. However, apply maximum pressure to the throat for a longer time (which = more bullet travel down the barrel) and you will wear your barrel out faster, a LOT faster. But speed costs - it always does whether it was Concorde v Boeing 747, Mustang v Fiesta, or .300 Weatherby Magnum v .308 Win. Keep pressures and performance down and the barrel lasts longer.

 

Then .... it's not even as 'simple' as that - manufcaturers do clever things to reduce flame temperatures while retaining the performance, and before getting into a mindset of single-base = good, double-base / high-energy = bad, just consider that RS52's specific energy is ~4,000 KJ / Kg and that of Hodgdon H4895 is 4,060 and VarGet is rated at 4,050 - VERY HOT propellants. So, push a 155 from a 30-inch barrel 308 to 3,100 fps + it'll cost you whether using an s-b Hodgdon / ADI propellant or high-energy RS52. Some true double-based products such as the Ramshot line (from PB Clermont) have been engineered to burn very cool because their primary market is military smallarms ammo and governments / miltary ordnance staff are very closely concerned about fiream and barrel life. Likewise, the former Olin Corporation (Winchester) St. Marks Powder Co. division of the General Dynamics Corp which makes all Hodgdon and Winchester ball powders and has been the primary supplier of propellants for US military 7.62 and 5.56 ammo for getting on for 60 years now.

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  • 1 month later...

I run 155gr scenars,155gr smks (2156s) and 155gr amaxs on rs40 in a 26 inch armalon barrel that gives 2930fps on 41grs, didnt bother to try making them any faster, the 2156 smks havent been chronied but very accurate on 41grs, jeez laurie, your like a ballistic programme,I am stunned by your depth of knowledge.

regards swaro

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