Transplanting Load Data

[Dill45]

Hey all,

     So I was looking for load data for a specific bullet for my 44mag and I can't find any data for it.  So I was wondering about transplanting data for the same powder using a bullet of the same weight.  Example being for H110 from Hodgdon, they have a 240gr Nosler JHP listed and the load data for it, yet I will be using a 240gr Magtech HJSP bullet, which isn't listed. 

     My question being, starting slow and low, would it be safe to attempt to work up a load using these numbers as a rough starting/end point?

Thanks,
Dillon

[bilmac]

If I've got you right, you want to just substitute one brand, same weight bullet for another brand. Maybe if you had worked up a load to get the very top velocity with the original bullet it may not be too good an idea. But if you are just using the data from a manual there should be no problem. I have done it for years, in fact I think a lot of older manuals never specified bullet brand, just the weight.

[necchi]

just to share,, I asked a question like that and here's what the masters said.

http://www.gboreloaded.com/forums/index.php/topic,190081.0.html

I've asked others in person, and all add cautionary notes,,be very carefull of high tech designed bullets as they have specific loads and properties,, But common bullets of similar design could/should be OK, "just start low", is what I heard from everyone

[Grumulkin]

So I was wondering about transplanting data for the same powder using a bullet of the same weight.  Example being for H110 from Hodgdon, they have a 240gr Nosler JHP listed and the load data for it, yet I will be using a 240gr Magtech HJSP bullet, which isn't listed.

My question being, starting slow and low, would it be safe to attempt to work up a load using these numbers as a rough starting/end point?

I do it all the time in guns with strong actions.  As long as you start low you can substitute data for jacketed bullets for equal weight bullets in jacketed and of  homogenous construction like Barnes bullets.  Increase the load cautiously looking for pressure signs.  For cast bullets, use date for cast bullets of the same weight.

In guns with weaker actions like most revolvers, lever actions, pumps and semiautos where pressure signs are much harder to interpret, I would still use cast bullet data for other cast bullets of the same weight.  In these guns, I would be more cautious in interchanging data for jacketed with bullets of homogenous construction as there could be enough difference in pressure to cause a problem.

One other suggestion; compare data in at least 2 manuals if possible and take the more conservative route.

[Dill45]

Thanks for the replies guys!

I would be using the loads in a lever action, a single shot, and a revolver so...

Also, I can't find a proper COL so, I would normally seat the bullets to the crimping groove, safe way to go?

Last question! I know that looking for pressure signs isn't a full proof way to go about max pressure, but I usually call it stops when the primers start to flatten out a bit (on revolvers most of all).  They aren't cratered or ruptured but surely some what flatter than known lower pressure rounds.  That a bad idea?

[wncchester]

"My question being, starting slow and low, would it be safe to attempt to work up a load using these numbers as a rough starting/end point?

Yes.


"Also, I can't find a proper COL so, I would normally seat the bullets to the crimping groove, safe way to go?"

Yes.


"I usually call it stops when the primers start to flatten out a bit (on revolvers most of all).  They aren't cratered or ruptured but surely some what flatter than known lower pressure rounds.  That a bad idea?"

No, but flattened primers is a bit more relivant with rifle loads.  Many - most? - handguns will come from together before you see any cratering.  Flattened primers more often show "excess headspace" than real over pressure.  About the only reliable pressure sign I've ever gotten in wheel guns is sticky extraction.   

 

[Grumulkin]

I would be using the loads in a lever action, a single shot, and a revolver so...

Also, I can't find a proper COL so, I would normally seat the bullets to the crimping groove, safe way to go?

Last question! I know that looking for pressure signs isn't a full proof way to go about max pressure, but I usually call it stops when the primers start to flatten out a bit (on revolvers most of all).  They aren't cratered or ruptured but surely some what flatter than known lower pressure rounds.  That a bad idea?

Seating to the crimping groove would be fine.

The signs of pressure are multiple (not just primer flattening) and differ among various types of guns.  You should not exceed the maximum loads listed in your manual and, in fact, most of the time my best load ends up being a grain or two below the maximum listed load.

Signs of low pressure include:

1.  Primer backed out above the head of the case.
2.  A lot of residue in the barrel.
3.  Soot on the case.

Signs of high pressure include:

1.  Primer flattened clear out to the edge.  It's normal for the center to be flattened somewhat.
2.  Primer cratering (too large a firing pin hole can do this as well).
3.  Pierced or leaking primers.
4.  Poor brass life (from loose primer pockets or head separations).  This can also be caused by poor brass.
5.  Sticky bolt lift, sticky extraction or sticky ejection.
6.  As a load is increased, groups will usually tighten a bit.  When they start to widen again it means that pressure is increasing a bit too much and that nothing beneficial will be gained by increasing the load further.

[Dill45]

     I think the head spacing makes sense about the flattened primers.  Because it seems they tend to flatten relatively easily in my revolver.  They are pretty flat all the way out though.  Not as flat as I've seen in some pictures but pretty flat.  I've never had an extraction problem say for some factory rounds from Hornady for my S&W 500.  Which have me worried a bit...

     I've never had any of the other problems mentioned so I guess it's all working well!

     Thanks again for all the help guys!