200 FPS with 40gr more powder?

[Samdweezel05]

I was cleaning the gun room this morning (actually got it done before I started to ponder) and I began thinking about my next build. I really like the 30 caliber stuff for no real reason. Sitting on the loading bench I had a bunch of different cases that I have loaded for in the past or still load for now. There is a question coming so bear with me. I lined them all up as follows....

6br - .223 - .22-250 - .30-30 - .308 - .300 WSM - .30-06 - .300 RUM - .50 BMG, Never loaded the BMG but I have brass here for it?

Then the questions in my brain started. I wonder how much better the .300 RUM is than the .300 WSM. My recently cleaned loading bench is now becoming a little more cluttered again as the reloading manuals come out.

To look at the 2 cases I would never think of them as being neck and neck, no pun intended. The .300WSM looks to be nothing more than a .308 that missed a couple of Jenny Craig appointments. Looking at some load data from a couple of bullet manufactures I see the .300 RUM does push the heavier 220gr bullets about 200 FPS faster but at the cost of almost 40gr more powder. Once you get down to the lighter 168-190gr bullets the FPS margin of victory for the .300 RUM starts to shrink to about 150 FPS over the .300 WSM and still with 20-25gr more powder.

And the question is..... Is there something magical that happens in that 150-200 FPS advantage over the .300 WSM that makes it a superior cartridge for long range bench shooting? When I shot my RUM at the range I always enjoyed the conversations that were started as I opened up the huge manly ammo box and pulled out one of those shiny monster RUM rounds when the guy sitting next to you is shooting his .220 swift. However, getting 75 or so rounds loaded from a single pound of powder to push 210gr VLD's was even slightly more painful than the recoil felt from all that powder and said bullet going down range.

 

[TonyR]

I/ve been asking myself the same question and I can't say that I have "the" answer but there is clearly a point of diminishing returns from incremental additional amounts of powder. Depending on what load manual you are looking at, the manual might actually be understating the capabilities of the WSM because most manualls assume that the bullets have to beated to the magazine length of a short action, but the 300 WSM does a lot better with the bullet seated farther out in the neck. I have friends that shoot the "Big 30s" and it seems that velocity is king when you are shooting at unknown distances because the trajectory is flatter but that it is probably easier to tune for accuracy at know distances with the smaller cases. If you want obvjective proof, go to the website for The Original Pa 1000 Yard Benchrest Club and look at what the winning 10 match aggs were shot with. You will see example of the biggest and the smallest but the 300 WSM and the 210 VLD are well represented.

 

[Samdweezel05]

Thanks for the quick reply. Yup, velocity gains you flatter trajectory and I had thought of that but how much flatter will it be with only 150 FPS gained? We are talking less than 5% in gained velocity.

 

[TonyR]

I believe there are some free external ballistics programs on the web that will let you answer that question. The Berger and Sierra published BCs seem to be quite accurate and these programs are very good at calculating the actual drops and even better at giving you comparable drops under the same assumed conditions. It really depends on what you are trying to do. Anyone shooting a 308 at 1000 yards has to be very careful with loads and bullet selection because the 308 can drop right through the speed of sound close to the target. That can be very exciting if you happen to be servicing that target. On the other hand, someone shooting "The Mile" might be willing ot pay almost any price for an extra 200 fps.

 

[Samdweezel05]

You are correct once again and I have one those programs and never thought to use it. The 210 VLD has 254" of drop at 3000 FPS and and 299" of drop at 2800 FPS. That's kind of scary.

 

[TonyR]

Yes it is. It is very interesting to watch the trace of a bullet through a set of "Big Eyes" as it works its way down range on a windy day. It's a wonder anyone hits any thing at those distances!!

 

[Samdweezel05]

So how underestimated do you think the .300 WSM really is? I would love to hear from people with real world velocity data. I would also have to believe the .300 RUM can be pushed faster than published as well. Damn it, I hate decisions.

 

[M700]

My .300 WSM moves 200 & 210 gr bullets at just over 2800 fps mv, 24" barrel.

My .300 RUM moved 200 gr bullets right at 3200 fps, or a tad under, 26" barrel.

That's a 400 fps difference - which in my mind is pretty significant. I happen to like my .300 WSM rifle a lot more than I liked the .300 RUM rifle I had, and there's also a significant recoil difference, so I'm okay with the lesser velocity of the WSM cartridge.

Both are good cartridges - and yes - there comes a point where powder appetite, recoil, muzzle blast and reduction in barrel life make the smaller cartridge more appealing to me.

Still, if a guy wants to move a .30 cal bullet as fast as it will go, it's nice to have the .300 RUM and the .30-378 Weatherby available... Someday I might make use of one of those cartridges in a long-range hunting rifle. Maybe. Meanwhile the WSM is doing just fine.

Regards, Guy

 

[TonyR]

I think M700 has it about right. The guys at Williamsport seem to run the 210 VLDs at around 2850 fps with the WSM but I'm not sure how long the barrels are. I know I did some analysis in QuickLoad that estimated about 3000 fps with a 31 inch barrel, and you can get a significant velocity gain with some of the slow powders in a longer barrel but that may not be practical for you.

 

[2644ever]

I've been thinking about the law of diminishing returns for a while too... I came to the obvious conclusions: 1) No matter what cartridge you are shooting, the chances of consistant 1st shot hits on X-rings at random and unknown distances are remote and more a matter of skills than a matter of hardware. 2) a .300 WSM wouldn't be at a disadvantage provided you compensate its inferior capacity with a long barrel: 28 to 30" are still usable on the field, after all you didn't sign up for Sniper School, otherwise you would be stuck with the .308 anyway. 3) Use that ballistic software, it will help put things in perspective: a 200fps difference between the WSM and the RUM, with the same Berger 210, relates to a difference of 110 yards. It will be like shooting at targets located 110 yds farther than the ones your buddy with the RUM is shooting at and the wind drift will be somewhat less because you'll actually shoot at the same distances.
Considering what you save in powder, wear and recoil, I think Ben Comfort's choice is still valid and it has morphed into the WSM.

 

[M700]

"Ben Comfort's choice is still valid and it has morphed into the WSM"

Interesting way of putting it, with a historical perspective. Nice...

 

[people]

I am shooting a 300WM with a long tube on it. It will push a 220gr SMK at just over 3,000fps. Now to answer your questions. The extra speed does not really matter unless you are using it for hunting. The extra performance really helps once your distance starts getting out there. Now if you are just going to make some holes in paper then you are just wasting powder and creating extra recoil.

Shooting a slower bullet only means you need to know something about external ballistics and how scopes work. Many do not to know or want to learn anything about that, and that is why .25-06’s are very popular with deer hunters here in ND. I can go on and on about slobs who use the .25-06 (Speed is good for 400yd shots) in my family and others I have watched from my hill side. The number of deer I have shot and for others because the 25 is not a good 400yd point and shoot rifle is truly sickening. Speed is good but it is not the end all be all for deer hunting. Speed will not make it easy to take a long range shoot or even a short mid-range shot.

 

[lynn]

When you want to get into real longrange shooting use 250 grains of VV20N29 behind a Harlow 800 grain borerider in your 50 bmg.You get 28 rounds per pound of powder.It will have more energy at 1000 yards than a 460 Weatherby magnum has at the muzzle.
Lynn

 

[people]

Lynn and here in ND they just want deer hunters to wound and kill deer. It is cool to use a bata-C mag but no 50 cal rifles for hunting. Kind of stupid I know. I talked to the Game and Fish guy and he feels that it allows a person to shoot tooooooooooooo far for deer. Seriously I am not making that up. Apparently he has not ever shot over a few hundred yds. I asked how far is too far. I was told that is nothing they can regulate. So my follow-up was then why can’t a person use a 50BMG rifle? I was told it allows a person to shoot too far. Back when I had a 50BMG there was no magic shooting fairy that miracle those 750gr A-max bullets on game. I can tell when continuing to talk is just wasting breath. Shooting long range is hard when you do not know what is going on but that is why we practice. Then it is doable.

That is part of the reason I hate “hunters”. To anyone who has ever noticed I always put the word “hunter” in quotes. In my book a hunter is a holier than thou person who is a slob and a hypocrite who has only fired one box of ammo (maybe) and will tell you he is set to take a 300 to 400yd shot at game. When they are throwing 2 to 3 inch groups at 100 with a coat as a rest. They will then tell me I am all kinds of F***ed up for killing deer over 1,000yds. I do not know how many deer I have had to put down because of slobs. These are the same guys who will take off hand running 100 or two hundred yd shots and never look for blood if the deer just does not drop. I have most of the game wardens cell phone numbers in my phone and I do not know how many times I get to call them every year.



Yes to make a long story short I am the bad guy for using rifles that the accessories on my rifle that cost more than the average hunting rifle and hunting scope.

 

[Laurie]

Looking at this from purely internal/external ballistics and target shooting perspectives, the first thing to be aware of is that all other things being equal (maximum chamber pressure, suitable burning rate propellants being available, barrel length, calibre and bullet design/weight etc) an x percent increase in case size and charge weight generates as a rule of thumb that increase divided by four in terms of bullet velocity.

That is a 20 percent cartridge size increase generates around 5 percent more MV. This only applies up to the point where the cartridge configuration moves into serious over bore capacity mode when you don't even get that level of increase in percentage terms, or maybe none at all. eg moving up from .300 RUM to a .300/.50BMG wildcat. In any event what you do get is less barrel life, a barrel that heats up much quicker, and more recoil.

QuickLOAD lists the .300WSM case as having 81gn water capacity, the .300 RUM as 112.5gn an increase of 31.5gn or 39 percent, say 40 to make things simple. Using our back of the envelope formula that should give an MV increase of around 10%. Looking at the Nosler manual, the top .300WSM MV for the 200gn Partition / Accubond bullets is 67gn Re22 for 2,944 fps; for the RUM and the same bullets: 98gn Ramshot Magnum for 3,191 fps, in both cases from a 26" Wiseman barrel, so hopefully reasonably comparable conditions.

That's 247 extra fps MV for 31gn more powder an 8.38% velocity improvement, right what the internal ballistics rule says.

Is 200-250 fps extra MV worth it in external ballistics terms bearing in mind the costs? Powder charge costs have risen by 46% assuming the two are priced the same per lb weight; recoil has risen from around 15 ft/lbs to 25 ft/lbs in a 17lb rifle; barrel life has reduced by 40-50%?

Using the example previously given of 2,800 v 3,000 fps for the two and running the Berger 210 VLD's G7 BC of 0.323 through the very good Bryan Litz Berger Bullets' ballistic program, we get at 1,000yd:

2,800 fps MV = 1,541 fps retained velocity and 6.3-MOA sideways movement in a 10 mph crosswind
3,000 fps MV = 1,689 fps retained velocity and 5.6-MOA sideways movement in a 10 mph crosswind

For target shooting at known distances forget bullet drop - it's not an issue provided your scope is mounted to put you in the centre adjustment zone at the longest range you shoot at and can still be adjusted down to be on target at the shortest range, usually 100yd for sighting-in etc. Only two things matter ballistically - is your terminal vel above the transonic zone (1.3 down to 1.0 Mach) and both are here. How much does a wind change move the bullet in relation to the size of the target ring size? A 5 mph quartering wind change sees the 3,000 fps 210 VLD move exactly a third MOA less than at 2,800 fps. The question is then is the extra recoil, cost and barrel life reduction a reasonable price for that amount of wind reduction in a typical scenario in a match?

Alternatively, shoot a 7mm/300WSM with 180gn VLDs at 2,900-2,950 fps which provides identical 1,000yd external ballistics performance to the .300RUM load in the wind and in terms of retained velocity, but with half the recoil and is therefore much easier to shoot accurately. That's why there are lots of Sevens - .284 Win, .284 Shehane, 7mm WSM variants, 7mm SAUM in long-range F Class and very few .300 Magnums of any size or description!

Laurie,
York, England

 

[Laurie]

"Ben Comfort's choice is still valid and it has morphed into the WSM"

Interesting way of putting it, with a historical perspective. Nice...

Yes, as a .300 H&H user, I can vouch for the fact the two give identical performance - not surprising as both have the same case capacity, the same SAAMI and CIP allowed PMax, and use the same charges of the same powders with any particular bullet. Subject to the usual issues of barrel throat configuration chosen / freebore and differences between two barrels of the same bore / groove size / rifling twist etc, you get the same results more or less. Because of the shorter case, the WSM has around 0.45" extra rifled barrel over the H&H within any overall barrel length so will give marginally higher MVs as a result. Both are allowed 65,000 psi PMax.

Ah ... but what about the short fat case efficiency? That gives a better burn, is more efficient = higher MVs, and reduces MV ES spreads. Since my .300 H&H matches WSMs fps for fps and has ES values in single figures, I'd say the short, fat efficiency issue is more myth than fact! Those guys in London who invented the .375 H&H Mag in 1912 and the .300 version a decade later either knew their stuff very well, or fell very lucky twice in a row. Just try telling any WSM or SAUM owner any of this though - light blue touch-paper and retire to safe distance!