Forums.NitroExpress.com

Home | Ezine | Forums | Links | Contact NitroExpress.com: Softs & solids, same loads, different velocities--why?

*** Enjoy NitroExpress.com? Participate and join in. ***

You are not logged in. [Login]

Main Index · Search · Active Topics
New user · Who's Online · FAQ · Calendar

Double Rifles, Single Shots & Combinations >> Double Rifles

Pages: 1

Spring
.300 member

Reged: 01/04/04
Posts: 104
Loc: Georgia

Softs & solids, same loads, different velocities--why?
#110898 - 02/08/08 05:55 AM

Something I've noticed as I've loaded for my DR the past several years is that I need different loads when shooting softs and solids to get the same FPS and POI. I was finishing up my bullets for next month’s safari last night and again came up with the same results.
I like my .470 bullets to fire in the 2,135 fps range; that's where it shoots the best. With my 500 gr Woodleigh softs I get there with 87 grains of RL15; with my 500 Woodleigh solids I get to the same point with 85 grains. Why the difference?

Post Extras:

Tatume
.400 member

Reged: 09/06/07
Posts: 1091
Loc: Gloucester, Va USA

Re: Softs & solids, same loads, different velocities--why? [Re: Spring]
#110902 - 02/08/08 06:28 AM

There are many reasons why this might happen. There might be a difference in diameter of as much as 0.0005 inch, which will affect pressure. The shape and bearing surface is probably different, which will certainly cause a change in pressure, and therefore velocity. Some solids are steel, but I don't think your's are. The seating depth inside the case is probably different, to get the same overall exterior length. And, I've probably left out some.

Post Extras:

Spring
.300 member

Reged: 01/04/04
Posts: 104
Loc: Georgia

cannilure [Re: Tatume]
#110903 - 02/08/08 07:32 AM

Regarding the seating depth, both the softs and solids are crimped at the same point on their respective cannelures. Could the fact that the solids may possibly taper differently than the softs make that much difference?

Post Extras:

Tatume
.400 member

Reged: 09/06/07
Posts: 1091
Loc: Gloucester, Va USA

Re: cannilure [Re: Spring]
#110910 - 02/08/08 09:14 AM

Quote:

Regarding the seating depth, both the softs and solids are crimped at the same point on their respective cannelures.

But, is the distance from the cannelure to the base of the bullets the same? Usually they are set so the distance from the cannelure to the point on the ogive where the rifling will be engaged is the same, and distance to the base varies. It is the depth to which the base is set in the case that influences pressure.

Quote:

Could the fact that the solids may possibly taper differently than the softs make that much difference?

Yes. Ken Waters, one of the best authorities on the matter, frequently found substantial pressure differences between loads that differed only in bullet shape.

Post Extras:

Spring
.300 member

Reged: 01/04/04
Posts: 104
Loc: Georgia

Re: cannilure [Re: Tatume]
#110924 - 02/08/08 12:18 PM

Considering that both the solids and softs I use are Woodleighs, you'd think they would basically be the same, and at a glance they appear to be. No doubt there's some sort of difference, I just don't know what it is. I'd guess it's the slightly more blunt design of the solids, which gives the bullet a tad more edge and pressure, allowing the use of less powder than its more aerodynamic soft cousin. Sound about right?

Post Extras:

GarBy
.224 member

Reged: 20/12/04
Posts: 39
Loc: Florida, USA

Re: cannilure [Re: Spring]
#110927 - 02/08/08 12:47 PM

I've reloaded Woodleigh softs and solids in 470, 500/416, 450 3.25" and 450-400 3" and there is ALWAYS a difference in the loads for the softs and solids. Woodies have a thick steel jacket covered by a copper jacket...but it's thin and the steel comes into play into the rifling. On the 470, to get the same velocity, it was as much as 2.5 grains....but generally 2 grains. The 450-400 is about 1.5 grains.
So not unusual at all to observe what you are seeing.

Gary

Post Extras:

Spring
.300 member

Reged: 01/04/04
Posts: 104
Loc: Georgia

Re: cannilure [Re: GarBy]
#110932 - 02/08/08 02:03 PM

Gary,
Thanks for the insight and I'm glad to see it wasn't just me that noticed the difference. My reloading experience pales compared to many around here and most of what I've learned has come from my own trial and error. Your thoughts let me know it's not just some whacky error in my reloading ways.

Post Extras:

wadeb
.224 member

Reged: 11/11/04
Posts: 40
Loc: Oregon, USA

Re: cannilure [Re: Spring]
#110953 - 02/08/08 11:57 PM

Spring, as Garby states, the woodleigh solids have a steel jacket which makes them harder than softs, which in turn causes pressures to be raised slightly and therefore raises velocity slightly. Ross Seyfried wrote an article in the double gun journal a while ago about this and stated that all you needed to do was to drop you load by 2 grains for the solids and you should get around the same velocity as you do with your softs. This you are already doing so you are on the money. I load my .470's at 89gr for the softs and solids at 87gr and I get the desired results.

wadeb

Post Extras:

DUGABOY1
.400 member

Reged: 02/02/03
Posts: 1340
Loc: TEXAS USA

Re: cannilure [Re: wadeb]
#110975 - 03/08/08 05:25 AM

Wadeb is right! Solids of any type are usually harder for the powder charge to push the bullet through the rifleing so pressure is increased. I have always found when a load is worked up for soft points, the load should be automaticlly lowered by about two grains, and worked back up till the rifle regulates the solids.

--------------------
..........Mac >>>===(x)===>
DUGABOY1, and MacD37 founding member of DRSS www.doublerifleshooterssociety.com
"If I die today, I have had a life well spent, for I've been to see the Elephant, and smelled the smoke of Africa!"

Post Extras:

NE450No2
.375 member

Reged: 10/01/03
Posts: 942

Re: cannilure [Re: DUGABOY1]
#110978 - 03/08/08 08:48 AM

All my Woodleigh Solids have a steel jacket.

Test with a magnet.

Post Extras:

Spring
.300 member

Reged: 01/04/04
Posts: 104
Loc: Georgia

Re: cannilure [Re: NE450No2]
#111354 - 09/08/08 03:14 AM

It's interesting--and certainly consistent--that I'm getting the same results when loading some softs and solids for my .375 H&H.
FWIW, when loaded with 71 grains of RL15 shooting 300 gr TBBC's, the load shoots at 2540-2550 fps. When loading my Woodleigh solids, 70 grains shoots at about 2562.
Thanks for your help in explaining the differential.

Post Extras:

Pages: 1

Extra information

0 registered and 56 anonymous users are browsing this forum.

Moderator: CptCurl

Print Topic

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled

Rating:
Topic views: 2941

Jump to

NitroExpress.com

Home | Ezine | Forums | Links | Contact