9.3x62 300 Grain A-Frame - COL & Load data Qs

[shootist~]

I've now had my 9.3x62 for over a year and have developed a good/accurate load for the 250 Nosler AB.
I generally shoot that load pretty well, but did not take it to Africa on my first go last month. In a head to head, I simply shot the 30-06 with 180s better. (And 100% good first round hits gave me excellent results on nine head of game, btw.)

Possibly I practiced with the 9.3 a little too much. (700+ rounds at the 1 year mark.) As mentioned elsewhere, I have become a recoil sissy in my old age. But enough history.

I hope to make a return to the dark continent next year - with the hope of hunting a Cape Buffalo. I would like to use the 9.3x62.

My goal is to work up a lower recoil practice load with 286 grain bullets (I do like to practice) - and then develop a hunting load that duplicates Dr Kevin Robertson's favored 9.3x62 loading - the 300 grain Swift A-Frame at 2,300 fps. He mentions this load as working well on buffalo for numerous clients in his The Perfect Shot II.

The 286 practice load is probably done. A starting load using RL-17 with the 286 A-F I tried yesterday ran 2,221 fps and ran just over a half inch at 100 Yds. Recoil was no biggie, even for me. At 3.358" COL I have lots of room in the magazine and it's a huge .229" off the lands. Bullet is seated just below the bottom of the [edit] neck, btw.

The 300 grain A-Frame uses up a lot more of the freebore, however. The same seater die setting gives me a COL of 3.283" with only .012" off the lands. The base of the bullet is a little below the bottom of the shoulder here - meaning it will probably be a somewhat compressed load with enough RL-17 to get me to 2,300 fps. (Probably ~59 grains based on QuickLoad and my prior use of RL-17 (and actual Vs) with the lighter bullets.

Do I need to be concerned with loading to only ~0.012" off the lands with the 300 grain A-F? I know this rifle was developed with a ton of freebore and this has me a little concerned. Or do I seat it deeper and worry less about powder compression (and higher resulting internal pressures).

Along with RL-17 I also have several pounds of IMR-4064 if that is a better choice. Plus H4350, etc.

Thoughts appreciated - especially if you have loaded the 300 A-Frame in the 9.3x62.

 

[jwp475]

You shouldn't get higher pressure by seating deeper

 

[Frederik]

Seat slighty deeper and rather work on what is accurate than trying to hit 2300fps.
Accuratte shot counts more than the energy of a faster bullet.

 

[Desperatezulu]

I wouldn't worry about the jump too much - presumably the rounds fit into your magazine ok, which seems to be the case if I understand your COLs correctly.
IMHO RL-17 is the way to go in the 9.3 (in other words that's what I use too! Ha ha)

How much powder compression are you talking about? General consensus is that anything up to 104-105% is ok, and a small amount of compression is good (allegedly more consistent powder burn and it will help resist bullet setback if the rounds in the mag hit the front of the mag under recoil)
I've used compressed loads of about 105% casefill (with a different powder to RL-17) in the 9.3 with no adverse signs.

Just to double check - are you certain you want/need to make the 300gr A-Frame work? The real life performance difference between it and the 286gr really cannot be significant. But it's making a 'significant' difference to your reloading complexity.

 

[375 Ruger Fan]

The Swift manual lists IMR-4064 as having the lowest SD on velocity. Max load is 56.0 grs to get 2319 fps out of a 24 inch, 1-12 twist barrel. Load density is 90%.

 

[shootist~]

Sounds like I'm overly concerned with a ending up with a compressed load. Just something I've avoided in the past, for some reason.

I'll seat the 300s a little deeper to gain a little more freebore and see how a starting load does.

Thanks for the replys!

 

[Desperatezulu]

I just played around with the software using my 9.3 data (barrel length, case capacity etc) and my burn rate for RL-17 and it doesn't get close to a compressed load by the time you hit 2300f/s... Obviously that's just a software simulation so the usual caveats apply.

Your specs will be different but I don't think you're pushing the limits.

 

[shootist~]

@Desperatezulu

Thanks. I'm using the Mk I Eyeball method to judge powder height and bullet depth into the case - but again I'm likely more concerned (read paranoid) than is warranted.

Proceeding slowly since heavy for caliber bullets in mid-bore loads are outside my experience.

 

[Desperatezulu]

@shootist~
As they say in the classics, there are old (paranoid) reloaders and there are bold reloaders - but there are no old, bold reloaders

I think a gradual build up to your desired velocity would be smart - most of us are impatient and want to try and get there sooner. Empirical data beats software simulations every time!

Keep us posted on how you go! I played around with 320gr Woodleighs and RL-17 but have got no further than about 2140f/s and a grouping that would make a sawn-off shotgun blush. So I am always curious in the heavy-for-calibre bullets in the 9.3.

 

[baxterb]

Be careful with that 300gr swift. They start life as a 300gr 375 and are swaged. When I loaded dummies with them (along with other brands) crimped in the groove, i promptly drove the bullet into the lands so that it stuck. The full diameter of the bullet is much farther forward than any other 9.3 I have tried.

 

[375 Ruger Fan]

@shootist~ your QL estimate of 59.0 grs of RL-17 to achieve ~2300 seems low. The Swift manual shows a 286 gr load using RL-17 and it's max load is 63.0 grs to get 2328 fps. The manual doesn't show a RL-17 load for the 300 gr bullet, but logically you will need 63-ish, not 59. BTW, 63 grs is 102% fill.

 

[andries 318 wr]

If you are not set on the 300gr, I would just stick to the 286gr Swift A frame. They will get the job done just as good if not better. I load them in my 9,3 with Norma 203-B and get to 2450fps with no problem.

 

[shootist~]

@375 Ruger Fan

I agree, my estimated V with the 300 gr AFs looks low - if based on the Swift Manual, but it's based on what I've actually seen with RL-17 (with the 250s) and just a few earlier this week with the 286 AF's. Does not mean it's reliable, of course.

My CZ barrel runs faster than the Swift manual shows, but slower than the QL projection. It's more or less in between the two reloading sources. I use different brass and primers than Swift.

Swift shows the starting load for the 286 AF at 58.5 grains of RL17 with a V of 2,224 fps.

I started at 57.3 gr of RL17 (QL projected 2,290 fps) and two using a Lab Radar ran 2,221 fps (2,215 & 2,2226). Pretty close to what I expected, btw. (I put the first shot on paper as a fouling load, but did not chronograph it.) The three bunched up nice and tight.

My estimate (at COL 3.283" = .012" off the lands) for the 300 AF and 59 grains of RL17 getting ~2,300 fps - is based on the QL 59 gr projection of 2,375 fps - with pressure of 51,647 psi. (Max is 56,565 psi.)

So I'm interested in seeing what others might have seen with a similar load. And yeah - it does seem to get a bit complicated.

 

[sgt_zim]

Can you work up a [marginally] better load with a 300 gr vs a 286gr? Almost certainly. But is the juice really worth the squeeze to get there?

with the 300 gr at 2350 fps, and the 286 at 2400, we're talking about a whopping 20 ft-lbs worth of energy difference (3679 vs 3658 ft-lbs). And that's if you can even get the 300 gr to 2350.

9.3x62 was made for shooting 285/286 gr bullets. play to its (and your) strength.

 

[WAB]

I was surprised at the drop off in velocity going from 286 to 300 gr bullets. I got 2450 with 286 gr and 2300 with 300 gr bullets. I went with the 286 gr bullet for my wife’s buffalo hunt. It was a one shot kill. (I use a Lott on buffalo)

 

[WAB]

I was surprised at the drop off in velocity going from 286 to 300 gr bullets. I got 2450 with 286 gr and 2300 with 300 gr bullets. I went with the 286 gr bullet for my wife’s buffalo hunt. It was a one shot kill. (I use a Lott on buffalo)

I should have clarified that both bullets were AFrames.

 

[shootist~]

@WAB
Good point. For some reason I thought the 300 gr A-Frame had the higher BC. But that is not the case.

 

[sestoppelman]

Sounds like I'm overly concerned with a ending up with a compressed load. Just something I've avoided in the past, for some reason.

I'll seat the 300s a little deeper to gain a little more freebore and see how a starting load does.

Thanks for the replys!

If you look at loading manuals, you will often see a big C next to a load, indicating a compressed charge. I prefer to not compress ball powders but extruded, compress away. Assuming of course the appropriate burn rate per the round and not a crazy charge.
And yes seating deeper does slightly increase pressures, it has too as you are basically decreasing the volume of the case that amount, if the charge remains the same. We know the opposite is true; seating out gives more space, and less pressure, with the same charge.
If you have a big magazine and long throat, you can seat bullets out farther and add powder. If you really want to get that 2300 or more, thats the way to get there.

 

[jwp475]

If you look at loading manuals, you will often see a big C next to a load, indicating a compressed charge. I prefer to not compress ball powders but extruded, compress away. Assuming of course the appropriate burn rate per the round and not a crazy charge.
And yes seating deeper does slightly increase pressures, it has too as you are basically decreasing the volume of the case that amount, if the charge remains the same. We know the opposite is true; seating out gives more space, and less pressure, with the same charge.
If you have a big magazine and long throat, you can seat bullets out farther and add powder. If you really want to get that 2300 or more, thats the way to get there.

I a bottle neck cartridge seating deeper lowers pressure since you are further from the lands. In a straight wall case seating deeper definitely increases pressure.
The 1 exception to deep seating in a bottle neck cartridge is one you are past .250 from lands pressure will increase

 

[shootist~]

Quick-Load shows increasing pressures as you seat deeper (reducing the space inside the case).
Obviously this would not be the case if you were initially jammed into the lands and just moving back from there.