416 Rigby and IMR 4350 Data Disparity

[MikeDeltaFoxtrot]

So I am working on some loads for my new Ruger RSM chambered in 416 Rigby. I will hunt with it next summer at the earliest, so I am in the preliminary stages. I bought some 400 grain Hornady Dangerous Game Solids, and some Hornady brass. I consulted the Hornady manual, and worked up a load. I loaded five rounds each at 81.0, 84.7, and 88.5 grains, which the Hornady book indicated would correspond to 2100, 2200, and 2300 fps respectively. Their test rifle was the same as mine, as Ruger RSM. I am using Federal 215 primers.

I tested those loads. They all ran well, with no signs of pressure. Extraction was smooth, and the primers were fine. The 81.0 grain load averaged 2171 fps, the 84.7 grain load averaged 2221, and the 88.5 grain load averaged 2343 fps. Hornady lists 88.5 grains as their max load for this powder.

When I got home, I consulted a couple of other sources for data, and noticed something odd. In the Barnes manual, they give two different sets of data for 400 grain bullets, one for the TSX and another for the banded solid. On the banded solid they give a minimum load of 89.0 grains with IMR 4350 and a max load of 97.5. The minimum is more than Hornady's maximum for the same weight bullet. For the TSX, they list 85.0 as the minimum and 92.5 as the max.

I then went to the Hodgdon website to check their data for 400 grain bullets with IMR 4350. They list 90.2 as the minimum and 96.0 as the max. Once again their minimum charge is smaller than Hornady's max.

I find this curious. The best theory I can come up with is that Hornady is being conservative in light of the fact that there are pre-war guns out their chambered in 416 Rigby that might not be able to handle more robust charges. The only other possible explanation is that there is a significant difference in performance between the Hornady and Barnes bullets, but that doesn't account for the Hodgdon data.

I normally stick to book data religiously, but in this case I may try to work up my loads into the 90-96 grain range listed by Hodgdon and see what kind of velocity I can get.

I am interested in what by AH brethren think about this. Does anyone have any experience loading the 416 Rigby with IMR 4350? Any ideas on the data disparity between Hornady, Barnes, and Hodgdon?

Thanks,
MDF

 

[Kycrawler]

Barnes bullets. And mono metal solids have their own data. A solid metal slug is harder to push down the bore than one with a softish lead core. You can get a chronograph for about $100. Real world info iut of your gun is priceless

 

[MikeDeltaFoxtrot]

Barnes bullets. And mono metal solids have their own data. A solid metal slug is harder to push down the bore than one with a softish lead core. You can get a chronograph for about $100. Real world info iut of your gun is priceless

If you read my post, you'll see that I did in fact shoot my test loads over a chronograph. This is not my first rodeo. I am hoping someone else has personal experience loading 416 Rigby with IMR 4350. Based on the dearth of responses so far, It appears that is not the case. I agree that Barnes data may be be directly applicable, but the IMR data should be.

 

[PHOENIX PHIL]

@MikeDeltaFoxtrot,

I think your assessment regarding Barnes being conservative and presuming early rifles in this caliber is likely accurate. It's how one stays out of court. Comparing Hornady to Barnes I would say is a bit of an apples to oranges comparison. The discrepancies can all be due to the bullet design. This may not be what you are doing here though, but it's hard reading your OP and separating one from the other.

FWIW, when I had a CZ in the same caliber, my H4831 loads crossed the 100gr mark by a fair amount. Just be slow and careful with the old caliber, as it seems you are being by the way. It's capable in modern rifles of pushing a big bullet at a fast rate. If you can put up with the punishment on the back side, a mono metal or bonded bullet will put a strong hurt on any animal.

 

[Von S.]

The more bearing surface the less powder due to friction .

Metal make up and weight change things. Pure copper is sticky.

Bore riders with driving bands and there is less pressure.

 

[Neil Molendyk]

I used the same setup last June on a buff and plains game hunt, CZ 550 Safari, worked up loads using Hornady DGX and DGS to zero the rifle and practice, probably 75 rounds. Off the bench was a proper bitch with recoil until I got smarter and used the LeadSled. I switched to Swift A Frame and Swift Breakaway solids, both 400gr, for the hunt. I think that the muzzle velocity was in the neighborhood of 2350 fps. One thing became immediately apparent between the Hornady and Swift bullets, when loaded to the exact same cartridge length, when trying to put 4 cartridges in the magazine, the Hornadys would not feed up the ramp into the breech (both DGS and DGX) whereas the Swifts (A Frame and Breakaway Solids) fed without a hitch. I suspect it was to do with the profile of the bullets themselves. The Swifts were accurate enough for hunting and worked flawlessly, no pressure issues and when hunting the recoil was unnoticeable, offhand and on the sticks. Adrenalin works wonders. The load in grains for the Swifts was considerably less than the Hornadys but the point of impact was almost identical. I managed to get the Swift softs and solids to shoot to the identical spot and I was very impressed in their performance on the animals I harvested. Bill Hober, President of Swift bullets suggested to me at SCI that the load for the Breakaway solids should be 2 grains less than the A Frames to have the same point of impact, he was right on. I can get the load I used to you tomorrow when I get back to my gun room.

**********

Here is the load data I used on my CZ 550 416 Rigby in Africa June 2018
Norma Brass (new for the hunt, up to 3 reloads per case developing the load and practice loads)

CCI 250 primers

400 grain Swift A Frame with 87 gr IMR 435o

400 gr Swift Breakaway Solid with 85 gr IMR 4350

3.625 cartridge overall length

No crimp on case

Note: Swift Reloading manual indicates 87 gr of IMR 4350 as their maximum load


*********
400gr A Frame recovered weight 398.4gr
400gr Breakaway solid recovered weight 395.6 to 398 gr

*********

When I was building up my test and sighting in loads I used Hornady DGS and DGX (more affordable than the other premium bullets) loaded up to 96 grains of IMR 4350, all grouped reasonably well but the point of impact was not much different than the Swifts using less powder as shown above.

When reviewing the reloading manuals they all seem to have different load data. I found that the Swift bullets performed well on paper and the critters, not saying that Hornady won't, but without starting a loyalty war, I chose Swift A Frame and Breakaway solids based on my research. I suspect that your thoughts on Hornady's reason for downloading the 416 Rigby is correct and they are covering their butt if their reload data is used in older firearms of questionable material or build quality.

 

[rookhawk]

At first blush, I would be concerned about typos from the data.

.416 Remington or .416 Ruger being confused for .416 Rigby.

IMR 4350 being confused with H4350.

Any one of these errors could get someone injured or worse. Be very careful because 416R and 4350 could mean a lot of things!

 

[Lbarr265]

Using IMR 4831 I noticed a similar discrepancy for the 416 Rigby. I checked 3 books (Nosler, Hornady, and Barnes) as well as the Hodgon website. I attributed the discrepancies differences in the testing. Each source has a different rifle, several used different primers, not all batches of powder are uniform no matter how much we wish they were, and of course they are all done on different days with potentially different temp/humidity ect. My response to the lack of consistency was load workups with 0.5 gn intervals until I hit 2400 fps at which point I called it good (and my shoulder said way past good). I started with the absolute lowest charge listed for any of the sources, which I think was the Nosler book.

 

[Shootist43]

I cannot comment on the use of IMR 4350, but I can tell you that I loaded my 416 Rigby (in a Ruger No. 1) with 92 Gr. of H4350 and got very good results at the range pushing a 400 Gr. pill.

 

[ChrisG]

The more bearing surface the less powder due to friction .

Metal make up and weight change things. Pure copper is sticky.

Bore riders with driving bands and there is less pressure.

The other thing I will add to this is that it is likely Hornady is posting data for their DGS and DGS. These are steel jacketed rounds. Compressing them to fit into the barrel is considerably more difficult than a softer monometal with driving bands. The other thing is that banded solids are always 0.001" smaller than nominal bore diameter to lower pressure. TSX may be slightly under too. Adding this up, the barnes bullets are smaller, softer and have less bearing surface on the sides of them, so more powder is needed to push them to the same velocity as a less "squishy" bullet like the hornadys are.

 

[Von S.]

Chris,

Just wondering something...

It seems that these days there is much advertisements about the new solids and that they go in a straight line better than the old steel jacket type.

Do you buy into this?

 

[ChrisG]

Chris,

Just wondering something...

It seems that these days there is much advertisements about the new solids and that they go in a straight line better than the old steel jacket type.

Do you buy into this?

The flat nose (meplat) is the key. It does two things, It stabilizes the projectile by moving weight more toward the front than a RN does, and it aids in cavitation, which is key to maintaining a nose-on orientation. There was a study done by a bullet manufacturer in South Africa in which he actually produced monometals with a sharp lip around the meplat of the bullet. some of these meplats were actually made with still inserts. here is the link to the AfricaHunting.com post about it.

https://www.africahunting.com/threads/more-stable-penetration-with-a-new-solid-bullet.14771/

From an engineering standpoint, it makes sense, the flat meplat tends to cause a cavity to form around the bullet if the bullet starts to tip within this cavity, it ultimately hits the cavity barrier, which straightens it out. Acting much like an arrow's vanes. There are other forces at work that cavitation solves, such as pressure changes as a fluid (tissue) flows around the bearing surface of the bullet at high speed. For bone penetration, it is easier to crush bone under the bullets nose than to try to divert it around (which is what a round nose does). Round nose bullets are fairly stable in a homogenous solid, but bone is anything but homogenous. Therefore, it is better to crush the bone beneath the hammerhead of a tip of the bullet (which also causes more damage) than to try to divert it and throw the bullet into a tailspin.

As to the hydrostabilized ones. To my way of thinking, they seem to function the same, except when they hit, they form a meplat which is just a bit larger than it would be possible to feed in the rifle, which increases cavitation and thus stability. The trick seems to be keeping the meplat uniform and smaller than bore diameter so that erratic cavitation doesn't result. They only have a taper on the nose to assist in feeding. I think if a manufacturer could get a long copper cylinder to stabilize and feed, they would.