QuickLoad uses 10733 psi for the start pressure for all A-frames and 3626 psi for standard
(even nosler partitions). Nosler uses lead and copper alloys whereas Swift are pure copper and lead?

Below is Hodgdon and Swift data for 7mm-08:

same barrel length, remington cases and primers powder load vel. psi
hodgdon data: 139gn hyd sp, OAL=2.800 h414 45.5 2710 47392
hodgdon data: 140gn swf sp, OAL=2.75 h414 46.0 2791 58067
Swift Data: 140gn, OAL=???, LD=92% h414 45.5 2813 na

hodgdon data: 139gn hyd sp, OAL=2.800 h335 37.5 2585 50090
hodgdon data: 140gn swf sp, OAL=2.750 h335 37.5 2647 58419

If one fits QL to the Hodgdon data for the 139gn Hornady, the Swift loads come out
nearly the same as the published velocity and pressure. So the A-frames
require more pressure to engage the lands.

Steve

So does QL get its information from actual measurements or is it theoretical based upon composition, materials, etc.? I just have to wonder about 10,733 or 3,626 psi. as opposed to say 11 ksi or 4ksi.
C.G.B.

My understanding it was from lab measurements.

Is hyd short for Hornady? If so, why, and where does Nosler come into it?

hyd is Hornady, only used as had same load parameters.
Below is Hodgdon data for Nosler partition:
Hodgdon Reload Data powder load vel. cup
Bullet: 210 GR. NOS PART imr7878 78.0 2895 52600
Bullet: 215 GR. SIE BTSP imr7878 77.5 2889 53400
Bullet: 210 GR. NOS PART imr4831 73.0 2877 50600
Bullet: 215 GR. SIE BTSP imr4831 72.5 2889 53000
Bullet: 210 GR. NOS PART imr4350 71.5 2895 52800
Bullet: 215 GR. SIE BTSP imr4350 71.5 2845 52900
Bullet: 210 GR. NOS PART imr4064 62.0 2843 53300
Bullet: 215 GR. SIE BTSP imr4064 62.0 2776 53100

nearly same pressures. My understanding Nosler uses copper and
lead alloys whereas Swift uses pure copper and lead. Other
solid copper bullets have driving bands which allow the extruded
copper a place to flow??
I went thru the OL bullet files for copper bullets and none of them
have Shot pressure higher than standard jacketed bullet. Some
even had lower pressure from the driving bands.

Thanks Steve.

If it's not too off-topic, what is the consensus on old Barnes X bullets?

I bought some 286-grain 9.3 Barnes X projectiles at a gunshow but have since wondered if they are all that safe to use in my thin-barrelled Zastava.

Cutting one open confirmed they are monos and, with no 'driving bands', I wonder if this is an issue analogous with those concerning double rifles where such bullets supposedly transferred a trace of the rifling to the outside, loosening the solder holding the barrels and ribs together.

quote:

Originally posted by sambarman338:
Thanks Steve.

If it's not too off-topic, what is the consensus on old Barnes X bullets?

I bought some 286-grain 9.3 Barnes X projectiles at a gunshow but have since wondered if they are all that safe to use in my thin-barrelled Zastava.

Cutting one open confirmed they are monos and, with no 'driving bands', I wonder if this is an issue analogous with those concerning double rifles where such bullets supposedly transferred a trace of the rifling to the outside, loosening the solder holding the barrels and ribs together.

I used to own a Ruger M77RSI in .30-06. This has an extremely thin-walled light-profile barrel.
I did shoot Barnes X through it without any issues, although not thousands of them. They were just too expensive for that.

sambarman338,
Here is some Hodgdon data from there manual
(published in 1998 and noticed is the same as their web based data!):

Hodgdon Manual Data: powder load vel. pressure
260 rem 100gn Barnes XFB h4350 45.0 3077 58200 psi
260 rem 107gn Sierra HPBT h4350 46.0 2997 50400 psi
260 rem 100gn Barnes XFB h414 43.0 2929 50600 psi
260 rem 107gn Sierra HPBT h414 43.5 2917 46900 psi
270 winchester 110gn Hyd HP h4895 45.0 3113 52888 psi
270 winchester 120gn Barnes XFB h4895 45.0 2950 58497 psi
300 Win Mag 125gn Barnes XFB h1000 80.0 3260 49099 psi
300 Win Mag 130gn Barnes XFB h1000 80.0 3125 41064 psi

I should note QL has 6527psi start pressure for the X and 3626psi
for the newer Barnes with driving bands.

Thanks guys, I won't throw them away then, just start loading very carefully.

From Steve's figures, the Barnes X does seem to lift pressures somewhat, even with bullets of shorter bearing area - not my 286-grain territory.

quote:

Originally posted by sambarman338:
Thanks guys, I won't throw them away then, just start loading very carefully.

From Steve's figures, the Barnes X does seem to lift pressures somewhat, even with bullets of shorter bearing area - not my 286-grain territory.

But remember, this is only the shot start pressure/engraving pressure. After that the pressures would probably fall to fairly close to the pressures of any other bullet.

This all takes place in the Nock's form.
Receiver ring diameter is probably a bigger concern here than barrel profile. I have no idea what that is on the Zastava though.

The shot start pressure is more like a non-linear offset added to the peak pressure (powder combustion
as a function of pressure, volume). Below is QL simulation of this:

338 winmag with Hyd 250gn, H4350,65.92gn

QuickLoad QuickLoad QuickLoad
Soft Start Pressure Base Pressure Peak Pressure Distance delta Peak
0 45662 50224 2.08
2000 49011 53940 1.84 3716
4000 51244 56810 1.68
6000 54035 59382 1.55
8000 56152 61764 1.44
10000 57384 64004 1.34 2240

Notice that for 0 to 2000 SSP, the change in peak pressure is 3716 whereas
from 8000 to 10000 SSP, the change is only 2240.

I should note that the original post of the Hodgdon data, Hodgdon measures
peak pressure with pressure transducer (either psi or cup) and correlates
to the QuickLoad simulation.
Sorry for the skewed columns. Looks ok when I edit but posting, does not see the spaces

What I take away from this is to use reload data for Swift bullets, be it the Swift manual or other source
and not use an extrapolated load from a regular bullet unless one backs off 1.5-3 grains, measure the velocity.
For example, the Swift manual has max. load for 7mm-08 with h414 of 45.5gn whereas Hodgdon has max. load of 47.0gn.
For H4350 Hodgdon has 50.0 max and Swift has 46.5 max.

Steve, it looks as though the 'soft-start' pressures do not get nullified later, that they add to peak pressure - a matter of some concern then, too.

Peter, as far as I know, the M70 Zastava is just a standard large-ring '98, apparently made with the old FN tooling. Atkinson seems to think it superior to the FN, though, being less likely to fly to pieces in a blow-up. That could mean, I suppose, that it might also be inclined to balloon as he says the German actions are, which could be a factor in any damage from that initial pressure.

Glad to see your spelling of Nock's form

Many years ago I didn't realize the pressure problems with Swifts. I went to Africa & hunted ele, Cape buff ,roan, & sable with my .416 Taylor Encore handgun. I loaded my Swifts at the same load as Sierras & Alaska Bullet Works bullets. Have wat thru the safari my Encore "froze up". Couldn't get the action loaded. On return I sent it back to SSK who made it. They in turn sent it back to Thompson. Problem was the frame had stretched making it inoperable. Thompson replaced the frame.
JDJones, the owner of SSK, told me to never use Swifts in Encore frames. I followed this. There are other options other than Swifts. I've used them on my other safaris, completed the Dangerous 7 & had no problems. I do shoot a lot of Nosler PTs & ABs & always load them a few grains under max in my Encores & XP-100s without any problems.

Those driving bands and other improvements made all the difference in the world according to the bullet makers of monolithic bullets that I've talked to. The early Barnes bullets tended to fail on game as well as accuracy, at least for me. Todays Barnes bullets have corrected those faults and seem to work as claimed.

Talking of bullets that give high pressures, has anyone had experience with the old Speer Deepcurls?

I bought some from the local shop (now closed) when looking for another Speer type specified in some manual. Trouble was, on opening the box I came on a warning not to use loads for other bullets, just those from the Speer website for them. On going to that website, I found it no longer mentioned Deepcurl at all. I finally found some loads but have still not been game to use the damned things.

Maybe I should open a museum of weird-and-dangerous bullets instead.

They guys who commented on their barrel thickness; read this; everyone else, optional.
Forget about your barrel thickness over the chamber! Bullet engraving affects the Entire chamber pressure; NOT just radial force. PSI acts in all directions; and modern CM steel will easily handle it. Not a Thompson Contender though, but it wasn't the barrel that failed; it was the frame.
Anyway, yes, solid bullets without driving bands, do have increased start pressures as talked about above. But it ain't your barrel that will be harmed when pressures go way up. As in over 80K Psi. (It will be the primer.)
Do not use them in double rifles though; they are not bolt actions in ability to handle pressure. Most of them.

quote:

Originally posted by dpcd:
They guys who commented on their barrel thickness; read this; everyone else, optional.
Forget about your barrel thickness over the chamber! Bullet engraving affects the Entire chamber pressure; NOT just radial force. PSI acts in all directions; and modern CM steel will easily handle it. Not a Thompson Contender though, but it wasn't the barrel that failed; it was the frame.
Anyway, yes, solid bullets without driving bands, do have increased start pressures as talked about above. But it ain't your barrel that will be harmed when pressures go way up. As in over 80K Psi. (It will be the primer.)
Do not use them in double rifles though; they are not bolt actions in ability to handle pressure. Most of them.

Perhaps we all need to consider the assumptions we made.

Mine was that Sambarman is an experienced reloader who has read enough to know that he needs to reduce start loads with these types of bullets, and he was concerned about the expansion of the barrel due to the harder bullet not being swaged down as much as a softer one, rather than the chamber pressure. The two are not necessarily directly related.

Back when monolithic solids first became popular here in Africa there were stories of the ribs coming loose on doubles after using them despite care being taken to maintain safe pressures. Of course, it's impossible to really tell what pressures you get as there's no way to test them in a normal rifle.

As you say, chamber pressure acts equally in all directions, but the stretching of the barrel as a bullet passes through it is not caused directly by the chamber pressure, but is influenced by the ratio of the force needed to cause the bullet to yield as compared to the force needed for the barrel to yield.

As an illustration, consider how much less force is needed to push a steel ball down a tube with a 1/32" wall and a given interference than pushing the same ball down a tube with the same ID but a 1/2" wall thickness.

Lot of overthinking methinks, with any bullet or combination changes its time to back off to starting loads amd work up to max inasmuch as we don't have the equipment to play this game and the Varble's between rifles amd calibers, Again its ballistic masturbation!