Testing Cape Buffalo Bullets for the .458 Win Mag.

frhunter13 wrote:

I have 2248 now with my Barnes 450 TSXFB COAL 3.30 in the magazine so I think 73g TAC is fine. TAC or H335 can get the 450 Barnes Solid to 2379 fps 3.29 COAL (their factory ammo COAL). There have been too many successes with these bullets to discount them. TAC can get the 500 TSXFB to 2194 fps 3.31 COAL. 3.30 COAL also probably with a tad less powder. There are many more options with US powder per this web site: http://www.barnesbullets.com/files/2014/11/458WinchesterMagnum.pdf

Oops it the the 500 Banded that gets to 2194fps. The 500 TSXFB can only reach 2040 fps.

Yep, but the PMP cases will be different - I just want to know their capacity too.

It's 95.2 with fired cases with the Hornady I am using. I measured this myself. I use the fired case capacity because that includes the chamber size.

PMP does not manufacture cases or load for the .35 Whelen. They do sell ammunition and components overseas but I doubt the .458 Win Mag will be amongst that. I know their ammunition is popular in England, Australia and northern Europe. I am waiting for the case water volume, forgot to ask that.

Once you bring the .458 we may find it wise to load some locally made GSC with S321 in PMP cases and test them.

The people I usually buy from like Natchezss and Midway and Cabellas and Cheaper than Dirt etc, do not carry PMP 35 Whelen of 458 WinMag. I see PMC sometimes but not in those calibers.

PMP Case mouth diameter.

The average case mouth diameter of PMP .458 Win Mag cases is .456" with less than .001" spread.

Today, Sunday June 4, 2017 I continued my efforts to prep my 458 Winchester Magnum and my 35 Whelen for upcoming adventures in Africa.

I took five shots with the 450g GC Flat Head bullets using BLC2 Powder.

Note that I based this first BLC2 effort on known loads for conventional bullets, planning to use velocity to gauge pressure in accordance with Quickload. I find Quickload accurate for relative changes to book loads, if not always so accurate with absolute calculations.

First Shot: COAL 3.278", 78g Powder No crimp: 2236 fps.

Second Shot same as first with gas check: 2230 fps. Realize the first shot was with a clean, lubricated barrel, so I take this result to mean the gas check made no difference.

Third Shot: COAL 3.25", 78g Powder Crimped : 2286 fps.

Fourth Shot: COAL 3.278", 79.2g Powder, not crimped: 2273 fps **

Fifth Shot: COAL 3.48" hand inserted, 81.5g Powder not crimped: 2316 fps **

There were no over pressure signs at all, and the action cycled smoothly.

So it looks like by simply crimping the loads of the 4th and 5th Shots I am in the 2325-2366 fps range. I consider this a success, and hope to verify the scope settings next time out. I notice that at 25 yards the bullets were hitting in the same place as the Barnes 450g TSXFB. According to the ballistics, the GC Flat Head drops off away from the TSX considerably after 100 yards.

The 35 Whelen needs a little more powder because I was getting 2657 fps first shot with a conservative load of BLC2 and Barnes 225g TSXB bullets. I can kick this up a bit to 2700 fps.

The rain is simply Southern Winds that carry Gulf of Mexico storms into our area. We had 16" in May which is one of our heaviest annual rainfall months. This often continues into June.

Quite.

Crimping could help, however the COAL must match a crimp point which looks possible here only if I use brass that has been fired several times so that it is longer. I did that with these rounds thinking I would crimp. Without seeing the velocities to estimate actual pressure, I am not taking the chance on crimping. I might add one that is crimped to fire if the others don't develop pressure though. So I will do that,

That rain - is it from a tropical off-shore system or inland convection?

So if velocity is still low, pressure slope and peak is still low - and then by crimping you can increase the pressure rise slope?

So I made four BLC-2 rounds to test with the GS customs. First I verified the safe load with known book loads of 77g for a 500g and 79g for a 405g bullet and then checked 78g with Quickload to get well under max pressure.

So I made

1. One 3.278" round without gas check at 78g.

2. One 3.278" round with gas check at 78g.

3. One 3.278" round without gas check at 79.2g which is closer to max load per Quickload with this bullet. I will shoot this last, maybe. Depends on 1 & 2.

4. One 3.48" hand placed round without gas check at 81.5g well under max at this almost to lands length. This is moving half way toward Lott length.

The effect of the gas check will be seen between rounds 1 and 2.

These are all un-crimped at present until I verify loads.

BLC2 is a commercialized US Military powder and goes by another designator. It is a allot like Win 748 actually. I know this is a good batch too. This will be my critical test with these bullets. Pass or Fail.

It is supposed to rain for seven more days (3 already) and that may flood the range, so this test could be this weekend or next. We got over an inch today.

The GS 450g .457 bullet with .461 gas check.

Yow. I measured the GS Bands at 0.4570 and the bullet at 0.451. The Barnes are .4575 outside and .443 in the channels. My leads are 0.459 . Outside of the gas check is 0.461.

Yes - that double base S321 is a very consistent propellant for the big bores. I use the next slower S341 in the .303. Must be the cleanest burning powders I have ever used because burn rate is not controlled by graphite coating but by chemical additives.

Michael the alert icon shows you have commented twice but the comments do not show. Same happened to mine in another category. I reported the issue to the forum service provider.

Wish I could get some S321 here in the states to play with. There is a powder here that seems to match it though. Hodgdon BLC2. I might try that with the GS bullets. BLC2 is slightly more dense, so the compression will be less, and I like that.

What I am afraid of is that the bottom band of the GS bullet is not wide enough or close enough to the base. As the bullet moves out of the case and before the first band hits the lands, there may be a point where there is not a good seal. This is why with lead bullets the gas check is always on the base of the projectile. This should actually be rectified in the bullet construction. There is no reason I can see not to put a band right at the bottom of this bullet. You might pass that recommendation on.

Sounds like a 458 Lott result. Who gets 3.6" out of a 458 Winchester unless its an oversize receiver? The max is 3.34 supposedly. Although by pushing one in by hand I could get out to 3.75". Back to the single shot. Too bad I can't get any S321 here in the states for the GS bullet.

The biggest penetration issue has always been bullet deflection and the rear-end side-swiping bone. A 450gr solid at 2,230 ft/sec which is known to stay nose-ahead all the way will do the job.

The Somchem factory results with the Barnes 450gr FB at 3.6" COL and using 77.2 gr S335 from a 24" barrel is 2,272 ft/sec.

I went with 61g BLC2 in the Whelen. 59g got me a shock when it brought my 250g Speers to 2700 fps. No pressure signs but I backed off anyway. Several other people are using the 61g of BLC2 with this 225g Barnes so I know it will at least get me over 2660fps without any doubt at all. My rifle is a bit tight so it reacts rather unpredictably. I might see anywhere between 2660 and 2800 fps with the 225.

I have decided to go with 74.7g Xterminator with the GS 450's, and I am debating sticking with the 2230 fps on the Barnes 450 TSXFB. What's another 12fps anyway. The brass looks perfect and the action is ok, maybe a little tight on extraction. So I think I will stick with the present load. The Xterminator load should get me around 2260 fps on the GS 450g flat nose bullets. I can't get any reasonable numbers with AA2230 using Quickload. It certainly does not agree with the book loads I have seen with this or any other caliber, or with the GS table of S321, so I believe he needs better data on that powder. That said, I will only go with something if all my sources agree more or less.

Until next weekend.

Oh I indeed know what you meant - I was referring to a bullet's relative level of reluctance to move out of stasis while the pressure rise is establishing its slope.

Alright then Inertia is the tendency to either remain in motion or in stasis, i.e. the tendency to not change in velocity whether at rest or in motion. There are no bodies at rest on this world by the way. I will say it this way to be clear: I am speaking of the in motion inertia, or perhaps you like momentum instead. The bullet needs momentum as it hits the lands or there will be a pressure spike.

Is that clear enough?

Regarding some physics terms: By inertia I referred to the definition of it as taught to kids in South African schools: In our case the bullet in a state of rest in the case mouth and being acted on by a force - the gas pressure increasing against it at a given rate:

The bullet's inertia is its relative reluctance to be moved out of its state of rest, thereby opposing the pressure and causing an increase in the rate of pressure development.

Resting against the lands that pressure rate rise is faster and the designed work pressure achieved sooner than had it been away from the lands. Bullets with full bore diameter pure copper surfaces - whether these are flat or grooved like the Barnes - have higher friction coefficients than bullets with narrow drive bands. Resting against the lands increases their reluctance to move, giving them a higher value of inertia. This level of inertia may cause too high pressure too soon as is well known. Barnes bullets indeed conform to this wisdom.

Bullets with narrow drive bands of bore diameter, and shank diameter same as that between the lands like the GRC, have very low friction coefficients and therefore lesser reluctance to move; they may need more inertia offered by the extra resistance assistance of the lands to ensure proper pressure development. If these low friction bullets do not achieve the velocity as predicted it means pressure development had suffered.

Maybe that is why I still have to hear of a US hunter bringing a .308W to Africa. A boring big game getter which, like the 7x57 does it with no bang or fuss. A meat machine as you say. The most popular big game cartridge out here.

Weight by weight the .303 will always be that 100 ft/sec behind the .308W - except with above 200 gr bullets when the difference becomes less.

My 308 Remington will match that 303 I bet. It has a detachable magazine customization too. One of those do the job vanilla guns that got so boring for me I don't use it much. Right now it is putting a Hornady 165g interlock out at 2810 fps. Simply a boring meat machine heh.

Heh. Think I will stick to the Barnes 225 because it get so many raving reviews except the few that complain it went clean through and Elk without expanding. Bah, only because it was probably a lung shot, which many many American shooters do because they are taught to shoot just behind the shoulder from an early age. It does the job with a super expandable bullet that tears a fist size exit hole, I admit :)

Virtually impossible to exceed the .458 WM cartridge rated pressure of 62,000 with rifle propellants.

South African S321 gives 61,227 psi with the Barnes TSX 450gr FB and 2,200 ft/sec. for a 3.34" cartridge length.

Heck, any bullet in the Whelen will be very good no matter the weight or make. I can not wait to see and handle that rifle.

The impact velocity of 180gr Speers and Sierras from my .308W and 30-06 on the shoulder of wildebeest at 100 yards just caused meat damage I did not care for, and at the time PMP brought out their ProAmm series which were much better. The older PMP bullets also made too much of a mess so PMP listened to us and made the ogive jacket thicker. Their mechanical locking has always been good.

Any bullet type and weight you like will be perfect. If I can not get you to under 250 yards of a kudu or gemsbok I may as well throw my hunting boots into a thornbush. I'll be carrying my .303 with 168 gr Peregrine VRG-4 at 2,620 ft/sec.

Ok. With the GS bullets freebore is 3.48 inches. Even more for the Barnes TSXFB, 3.75". This explains the erroneous Quickload estimates for Win 748. That explains allot of my results actually. It is not as though I can ignore the 3.278" required to clear the box with these bullets, or the 3.30 to clear the Barnes, however I will not get the velocity or pressure predicted by Quickload. So, what this means is that I must figure out how to address this. My gut tells me the freebore length is the real number to go by as long as you have room in the 3.278" case for the powder, with some reduction of powder to account for the "start up ramp" to get the bullet to the lands. I am an engineer by trade. We build rockets, so this is an interesting problem to chew on. One way is to use the velocity as the pressure gauge, and experiment allot. Ok, I am good with that :)

My load books (Lee, Sierra and Lyman) tell me NOT to place the bullet against the lands because the bullet needs some initial inertia at that point. You don't get inertia without movement This is accepted mantra here in the USA. Pressure spikes can result. What you are saying is that I have a single shot rifle and that is not true frankly. What I am saying is that the freebore decreases pressure at the cusp, and at present there is no way to account for it. I will measure the freebore with those bullets today. What I suspect is that I CAN hand place a round in the chamber that is CLOSE to the lands to fire first . Then the other, shorter rounds can go in the box. With the same powder load these would go a little faster than the longer bullet unless I load the longer bullet with a more powder to get even higher velocity. But the difference might be less than all this experimental effort would be worth. Accounting for different bullets in a pressure situation? Hmm.

I would rather somehow account for the feebore and build all of the bullets the same.

Quickload should have a freebore input, but talking to that guy is like talking to a wall.

To whit. I fired the 35 at a max COAL. Then I pushed the bullet in with that same powder charge. What I got was a 10 fps increase in velocity. Yes there was a pressure increase but not nearly that predicted by Quickload. This is why I like book loads, but they don't account for freebore either.

Anyway I told you that I had 250g Speers SPFB going at 2600 fps. You said they are crap bullets. I don't think so because they are used extensively in Canada for Moose and the occasional Bear. In fact overall they were rated higher than the "premium" bullets by poll in Canada. Who cares about an occasional Jacket separation? The animal is just as dead. I am going with the 225 TSXFB because that bullet outperforms it's weight and is a great penetrator.

Why the comment about round nose? That GS flat point has a BC of .15. Frankly that sucks. It is for close work only. The Hornady steel clad have a much higher ballistic coefficient, as does the 450g TSXFB I have going 2230 fps. and certainly can get to 2242.

1. If I could get 2,600 ft/sec with a 250 gr bullet in .35: calibre that is exactly what I would go for - but no doubt you already have the 225s. Relative to .35 diameter a 225gr bullet indeed is " light". 250gr would be medium, and 275 gr in the normal heavy range. 300gr would be "heavy for calibre".

2. You no doubt know that a round nose bullet has about 2x as much air drag as the FP, and furthermore it has less stability inside the varying density tissue of the animal.

3. The QL loads do not consider the freebore of the .458 chamber - it does not know what any rifle's free bore is but assumes all bullets will be loaded against the lands. That is the very reason powder charge is built around a maximum required pressure per load to reach the velocity for that pressure: all loaded with that built-in inertia supplied by the rifling. That pressure is based on the assumption that the bullet will rest against the lands as they should - which will cause a certain (higher) inertia which will allow the required pressure to build up to give the required velocity.

Without the lands causing more inertia to the bullet this low friction projectile jumps out easily and goes along before the pressure increase could reach the required rate; neither will it attain the peak pressure as used by QL.

It's 3.34 MAX on the 458 and the Whelen. not 3.4. Sorry for the confusion.

Oh, and if I know I have that freebore, the books and Quickload calcs are not exact or fact.. To realize this fact is a WIN. The loads can actually consider the freebore!

Oh by the way, I discovered that the MAX COAL of the 8x57JS is 3.25". So, all of these conversion of Mauser Rifles must deal with the fact that the box and the bolt throw are designed for 3.25". My 458 Mag was once a Mauser 98, so the fact that it will take 3.30" Spitzer shapes is above the 3.25" However with that square shaped GD solid it will only take 3.278". This can usually be compensated for in powder selection to a limit. The round nose Barnes Solid is 3.29", and the rifle box can take that length and shape. I expect a large company like Barnes took that into account. The barrel is a 458 Magnum barrel so it has much more freebore than the box and bolt limit. So, If I wanted a single shot I could get more power out of this rifle. However, the bullets would not land in the same place as those in the box. So I guess if I purchased a CZ 458 Mag I could use 3.8" COAL so they say. But then I am stubborn! The CZ is longer and heavier, and I have this one!

This goes for the Whelen as well, by the way. A 3006 (thus the Whelen) has a max COAL of 3.4". Guess what, the Mauser conversions - 3.25" unless it was conservatively built.

Well I came to that conclusion as well. The chrony is your friend! Keep saying that. I like to cross reference and start light especially if there are discrepancies. The fact that there are a dozen people I am aware of using the RE 15 load in the Whelen and because I already had a 250g RE15 load that worked in the Whelen to 2600fps, I am apt to go right to 58g for the 225g Barnes. This will give me close to 2700 fps with the ability to go all the way to 60g but only if I need to.

Oh. I must say that 458 packs a mean wallop! Didn't hurt me, but I wasn't falling asleep, heh. The guys in the booth next to mine told me I "need a silencer on that thing". The Whelen is much nicer to shoot, and at one time I thought IT was a brute.

I think why they do not give a maximum powder load is because they give a maximum velocity and a maximum pressure. When you reach that velocity you are at that pressure.

Maximum propellant loads given by reloading manuals have got many reloaders without a chronograph into over pressure condition. Because velocity=pressure it is safer for the reloader to use that as his limit. When the velocity is not reached yet the next step is an increment more propellant.

I would not jump to any such conclusions. The results I got today in the Whelen were exactly what was predicted by Quickload. I had a very unusual jump in velocity with the Sierra bullets and the IMR 4895 giving me 200fps OVER what was predicted. This did not show up in the mapped pressure curves. The whole business of proximity to the lands and seating depth were PERFECT and I accidentally zoned in. Only difference is the Barnes bullet is a little longer so not as much air in the case, plus one is a boat tail and one is flat. I was just checking to see if I got the same effects, and instead am back in the predicted zone. However there are people using the RE 15 with the same coal and the Barnes bullet and show actual measured results, so I will go there next with the 35 Whelen. Slow is NOT a bad thing actually. You can actually get higher velocity that way sometimes. Not with lighter bullets though, it's a bad idea. 225g is NOT a light bullet, heh.

I simply believe the GS chart is incorrect regarding Win 748, and 72 g is the STARTING load given, not the max velocity load. You must read that chart very carefully. They don't give you a max powder load. Kinda weird actually.

On a side note my Hornady 10th book shows for a 500 g DGS bullet you get about 2000 fps with 76g of Win 748, so I got over 100fps faster than that today with the GS. I noticed that a few days ago and thought the expected 2319fps would be the result of less friction with the GS bullet. Not so I discover. I plan to try Xterminator next because Barnes uses 74g of that to power their 450g Banded Solid with a COAL of 3.29 measured. The banded solid does fit in my gun barely, but I discovered that the GS bullet will NOT go down into the mag at 3.31 COAL. The next GS cannelure is with a coal of 3.278, which does allow the GS bullet to work. Therefore I will use 73g of Xterminator, which by the way is in line with the GS recommendation.

I did notice that the only gas check is the bands, and these bullets go into my cases mighty easy. It is possible that my barrel with the shallow rifling is not compatible with these bullets. I have not given up yet though. I am happy with the Barnes 450g TSXFB results. They are very, very accurate and I have sighted in on them with the BDC scope. 1.7" main cross hair at 100 yards and the second pin is zero at 200 yards.

Their website showed that 72gr 748 gave 2,350 ft/sec, and 73gr of our double base S321 achieved the same with that 450gr FN.

Michael do you think the small decrease in your case capacity is the cause for this? With a standard barrel there should be no blow by. Maybe you could measure both the driving band diameter as well as the shank diameter just to have confidence about that.

There of course is the most likely reason: your pressure peak is too late and below the rated value: These bullets must be seated to positively touch the lands to ensure the pressure peak on the bullet base at the correct moment after leaving the case mouth. I would load one or two rounds like that, hand feed them and do a chrono test. Their Q.Load figures would be based on the standard seating as mentioned and your case capacity. In practice your case capacity was as programmed but the free bore was too much, preventing the proper pressure rise slope.

Regarding the Whelen: I have a lot of confidence in RL 15 and found IMR 4064 to also be accurate but exceedingly sooty. Anything slower than RL15 with that lightweight bullet in that wide chamber will run out of initial pressure too soon, and I believe RL15 is even too slow.

4895 should have been be the ideal if the Barnes were seated properly. RL12 (not made anymore) and our S321 are the equivalents. That slow MV indicates too late pressure peak and that peak is below the rated value. I would have gone to RL 10 if the seating depth stayed the same. Do you know how far from the lands your first contact radial on the ogive is?

Well some good news about Barnes and some bad about the GS solids shown above. According to Quickload and using the Quickload model given by GS I should have gotten 2319 fps from 75g Win 748 and a coal of 3.278 with the GS Solids. I actually chronographed 2132 fps from that load, so it was a bust. More than that will be heavy compression. It printed well against the other shots from the 450g Barnes Solid and the 450 Barnes TSXFB, however the Barnes banded solid was 2285fps and the TSXFB clocked 2230 fps. pretty much as predicted.

The Barnes banded solid and the tsxfb are a good matched pair and I am certain would be adequate for my purpose. However I have only 19 of the banded solids now and was hoping the GS could take it's place.

I don't know if I am getting too much blow by or what, but I will try that same load for the GS solid that's powering the Barnes solid next outing. If that does not kick it up there, then I will give up.

I was also disappointed by the 35 Whelen. I tried the same 56.3g IMR 4895 load that is pushing my Sierra SPBT 225g at 2800 fps, substituting the 225g Barnes TSXFB and got only 2545 fps. However there is a remedy for this with IMR 3031 or 4064, Hodgdon BLC2 or Reloader 15. I am favoring 58/59 g RE 15 because there are quite a few people getting 2700 fps with that and good accuracy. It is a known recipe, although you could fool the powder maker because it's not on his list.