Fast powder in 308

[Hengehold]

As a Palma shooter I am used to using the Varget and 155gr SMK to be competitive. I am under the impression that slower burning power is used generally used with heavier bullets and faster powder is used with lighter bullets. Based on this understanding, I find it a little confusing that shooters use faster powder (faster than Varget) such as H4895 or IMR 4064 to shoot 185gr + bullets in a 308. Is this kind of recipe just left over from the M14 days when a certain burn rate was needed to cycle the action?

While Varget fills the 308 case I would think that with a longer freebore (think the US F-Class Team chamber) there would be enough space in the case to use Varget or slower powders.

Is there something obvious that pushes people to use faster powders for heavy bullets in a 308 and I just don't see it?

Thanks,
-T

 

[ShootDots]

I do not shoot F-T/R nor do I shoot Palma. However, there are certain "principles" if you will, that are generally true. Lighter bullets out of any cartridge, is better served by the "faster" powders that are still in the "normal" realm for that cartridge. Example: 60-80 grain bullets in a Dasher are better served with "faster" powders, than slow powders. On the other hand 105+ class bullets are better served with powders that are slower than those used with the 60-80 grain weights.
If I were to shoot Palma with 155 / 155.5 bullets out of a .308, I would use IMR 8208XBR. It is stable, very fine grained and perfectly suited for that weight bullet in a 308. Would other powders work? Of course! But would they extract everything out of that case, using that bullet weight, as 8208 would >>> I would bet not...

 

[Ned Ludd]

I use both Varget and H4895 in .308 loads with 185 and 200 gr bullets. Although H4895 is "faster" than Varget, it is still well within the useful range for .308 bullets of 185-200 gr. Varget is not a particularly high energy powder. In general, you will get about 25 fps greater velocity at the "sweet spot" with H4895. Pressure as predicted by Quickload is comparable to Varget or perhaps just a tick higher. 25 fps is not a sufficient increase in velocity to provide a major benefit in terms of performance (wind resistance); however, if all else is equal (primarily meaning comparable precision), I'll take the extra 25 fps every time. With the 200s, I have found I'm reaching a point where there is a noticeable difference in recoil between Varget and H4895. With H4895 the recoil impulse is slightly sharper, more like a "crack" than a "push". It's not a huge difference, but it is noticeable. I probably wouldn't choose H4895 to push the next heavier weight class of bullets (210s, 215s), but it works fine in my hands with bullets up to 200 gr.

 

[swadiver]

Imr 8208 xbr

 

[Dgd6mm]

185's and H4895 in a 11 twist button rifle CBI barrel 30". It works just fine, and I believe if I had a 1-10 twist I would try the H4895 with 200 20x.


Don Dunlap

 

[spclark]

Hi Trevor! I shoot Palma, with 155.5's too.

I shot Varget for several years until it grew scarce, Used RL15, N140 & N150 after that for a couple of years. Expensive but worthwhile. Then I tried 8208XBR; had some for a year, bought intending to try it for Palma loads but got sidetracked with 6XC when I found it worked exceptionally well with that contrary to several folks' opinions. When I got 'round to trying it I liked what I saw. Tried it with 185 (Juggs) but not enough to find a load I liked.

Used it for five or six years until a Team member turned my head to Benchmark, which is what I've used ever since.

This article may help you reconsider why burn rates aren't gospel.

Finding the right combination for bullet weight & accuracy can be tricky, why it's often said just pick a load that others use successfully & go shoot. Generally slower powders won't build pressure as fast when pushing heavier, long bearing surface bullets through a bore as with faster powders, so there's that aspect to consider when choosing a propellant.

You coming back to Winnequah in a couple of weeks for 2017 Midwest Palma? Be good to see you there again.

 

[M14AMU]

Just because John Doe is using powder XYZ DOES NOT mean that XYZ powder is going to produce a winning score for Joe Blow! Joe Blow has experimented with and tried powder XYZ but lo and behold the best performance with his particular rifle is delivered by using a powder not normally considered by the majority of shooters! Rifles are like people; all different and unless adequate testing is completed the best results probably won't be attained!

 

[Alliant Reloading]

Please consider AR-Comp(TM) in this application.
It is a little slower burning than IMR 8208XBR, so we see higher velocities or less pressure at equal V in our testing. It delivers low sd's and fills the case nicely. You should be able to make very accurate ammunition with AR-Comp.
They are both excellent at temps.
Shoot well,
Paul

 

[Heman]

I've ran Varget for the past 7 years in the 308 palma rifle and the last 3 in the 223 palma rifle. As soon as I'm out I'm switching the N140 just because it is cooler burning and N150 and N160 have shot so well for me in 260 and 243 respectively.

My Varget velocities in the 308 rifle are 3,050fps with 2156 SMKs, 2920fps with 168 Hybrids and 2780fps with 185 Juggs.

 

[spclark]

As soon as I'm out I'm switching the N140....

Watch your charge weights carefully with that.
I (and others) have found it useful but sensitive to pressure at higher ambient temps around here in summer, stayed with N150 which seems more stable & every bit as effective.

 

[Kurz]

I find it a little confusing that shooters use faster powder (faster than Varget) such as H4895 or IMR 4064 to shoot 185gr + bullets in a 308.

While it might seem counter-intuitive to use faster powders with heavier bullets, it's really isn't. Larger diameter, heavier bullets eat up case capacity. In order to get them moving efficiently, it is necessary to use the faster powders.

Please consider AR-Comp(TM) in this application.
It is a little slower burning than IMR 8208XBR, so we see higher velocities or less pressure at equal V in our testing. It delivers low sd's and fills the case nicely. You should be able to make very accurate ammunition with AR-Comp.

I might agree with your assessment when discussing just the 155.5 grain bullets. But when the weight increases, I generally I have to switch powders. Several of us who shoot together, have found a great recipe for the Berger 155.5 and IMR-8208 XBR. Plenty of velocity and excellent accuracy. Maybe it was the lot number but we did not get the similar results from the AR-Comp. But given the number of variables, it could be one or a combination of variables which yielded that data. That's why we usually resort to doing our own testing because sometimes things change. When we shoot the 200 grain+ bullets, Re-15 seems to give the results we like. Different strokes...

 

[Nature Boy]

How much VV140 are you guys using on your 155g bullets?

 

[spclark]

How much VV140 are you guys using on your 155g bullets?

Um, kind of a loaded question to put to us - what any one of us deems safe for our use and equipment may not be for yours.

Read this essay elsewhere on this website, with the suggestion that a safe starting load to begin testing with is 10% off what the other listed propellant charges are for 155's.

(Maybe not John Whidden's though, he likes things on the edge!)

None of us want you hurting your equipment or yourself.

 

[Nature Boy]

Um, kind of a loaded question to put to us - what any one of us deems safe for our use and equipment may not be for yours.

Read this essay elsewhere on this website, with the suggestion that a safe starting load to begin testing with is 10% off what the other listed propellant charges are for 155's.

(Maybe not John Whidden's though, he likes things on the edge!)

None of us want you hurting your equipment or yourself.

I understand all of that. Thanks

 

[Down South]

I use both Varget and H4895 in .308 loads with 185 and 200 gr bullets. Although H4895 is "faster" than Varget, it is still well within the useful range for .308 bullets of 185-200 gr. Varget is not a particularly high energy powder. In general, you will get about 25 fps greater velocity at the "sweet spot" with H4895. Pressure as predicted by Quickload is comparable to Varget or perhaps just a tick higher. 25 fps is not a sufficient increase in velocity to provide a major benefit in terms of performance (wind resistance); however, if all else is equal (primarily meaning comparable precision), I'll take the extra 25 fps every time. With the 200s, I have found I'm reaching a point where there is a noticeable difference in recoil between Varget and H4895. With H4895 the recoil impulse is slightly sharper, more like a "crack" than a "push". It's not a huge difference, but it is noticeable. I probably wouldn't choose H4895 to push the next heavier weight class of bullets (210s, 215s), but it works fine in my hands with bullets up to 200 gr.

+1

​

 

[Heman]

Steve,

I played around with it and got the charge's figured out (have to find where I wote it down), but I'm not afraid to run stuff on the edge either.

 

[GrocMax]

This may be of interest to 308 shooters, a burn rate chart based on a CIP 308 with the same bullet and a fixed powder charge-

https://www.norma.cc/en/Ammunition-Academy/om-handladdning/brinntider-for-krut/

Its a few years old but still might be useful for some.

 

[spclark]

...I'm not afraid to run stuff on the edge either.

Shawn I know you're a responsible reloader, it's those with less experience I leave the caveats for, the folks newer to reloading who might have problems thinking this stuff is linear ("If a little more's good then a LOT more must be better, right?") when it's not.

 

[Laurie]

We tend to use slower burning powders in many cartridges than handloaders of a previous generation. In Europe, N140 was the norm in 308 for 150-175gn bullets for many, many years - and is still 'the norm' for many in the UK today. It is in fact, not a particularly 'fast burning' powder for the cartridge. For some reason, Viht's maximum N140 loads are much lower than they used to be, and are in practice so low that they are verging on being 'starting' rather than 'maximum'. European 308 Win shooters have long exceeded factory maximum charge weights - and by a lot at that - even when loading for very short freebore chambers. ie 155gn bullets in Palma 95, Bisley 150 and similar. Factory Remington 700 VS, Police, SPS Varmint etc chambers allow still higher N140 charges.

N150 is common here for bullets heavier than 175gn, and to be honest I've preferred this one for 155gn class handloads too, although MVs are often a bit down.

Going back to the wider question, 308 Win is an exceptionally flexible, 'well balanced' cartridge making it very propellant tolerant. That is because the case capacity matches the bore size very well, and as Bryan Litz has long argued, 150-175gn weight bullets are on the light side for .30-calibre, not 'normal weight' at all. Go back to Ken Waters' 'Pet loads' for the 308 win, the massive 'Update' version of his 308 handloading articles originally published in July 1979 in 'Handloader' Magazine, and you find many propellants that will surprise modern users of the cartridge.

To take 165/168gn bullets, we have (recommended) loads for IMR-3031, WW-748, H322, H4895, IMR-4895, WW-760, IMR-4064, N202, IMR-4320.

180/190gn bullets have all those plus Hodgdon H335 and BL-C(2), also Norma MRP (!), IMR-4831, and WW-785 - a much wider burning rate range than most would consider nowadays. In particular, surprising to modern 'eyes' is the use of Hodgdon H322 (this would be the Scottish ICI Nobel manufactured version then, but today's Australian ADI made stuff won't be very different) and IMR-3031, both regarded as FAR too fast burning for this combination. Yet, the MVs are perfectly respectable - high even for 3031 - and accuracy was regarded as superior with match bullets. I've often thought IMR-3031 an underrated powder in this role and suspect the 'problem' with it hasn't been one of performance rather it being 'old-fashioned' and also poorly suited to mechanical powder measures with its long grain kernels. The relatively fast burning Norma N202 (same thing as Alliant Re15) produced the most accurate overall number of several score combinations under the old 190gn Winchester BT, 40.0gn for 2,361 fps from a 24-inch barrel Winchester Model 70 Target at what was described as 'moderate' pressures. H322 was regarded as an excellent choice for shorter distance match loads, and was also used in the larger case 30-06 in that role by many bolt-rifle shooters in those days. (Too fast burning for the M1 and M14/M1A semi-auto rifle mechanisms where 4064/4895 was the standard.)

KW didn't have any Viht grades in his tests as the marque wasn't being imported into the US in the mid/late 70s.

A final thought on Viht burning rates in the cartridge is that N135, considerably faster burning than N140, is the canister version of Viht's standard powder for 7.62X51mm NATO ball ammunition with 146-150gn FMJBT bullets.

 

[DRNewcomb]

While it might seem counter-intuitive to use faster powders with heavier bullets, it's really isn't. Larger diameter, heavier bullets eat up case capacity. In order to get them moving efficiently, it is necessary to use the faster powders....

As long as that can be done within safe pressure limits. The reason for using slower powders is that they tend to spread the pressure curve out more, with not so rapid a pressure rise. Testing the theory at the extreme would be using 40 gn of Bullseye behind a 180+ gn bullet. The results would be spectacular and probably somewhat bloody. So, as long as the reloader takes into account the peak pressure, including temperature sensitivity issues, and stays under the maximums, things should be good.