Reloader 17 in QuickLOAD

[Erik Cortina]

Why is it that when I compare loads between H4831SC, H4350 and Reloader 17 on QuickLOAD, RL17 hits max pressure before the other two and shows less speed. How come everyone says that you can get more speed from RL17?

In my 6.5X47 Lapua, QuickLOAD shows about the exact speed for both at max pressure, I wonder if I have the wrong powder properties for RL17.

6.5X47 Lapua
139 Lapua Scenar
2.850" AOL

39.28 gr. H4350
63,116 psi.
2,847 fps.

38.3 gr. Reloader 17
63,099 psi.
2,843 fps.

According to QuickLOAD, H4350 is 4 fps. faster than RL17 at the same pressure.

Can anyone help with this issue, am I missing something?

Thanks.

-Erik

 

[Laurie]

Erik,

despite the new deterrent technology, Re17 does seem to be slightly faster burning than H4350, alsthough Alliant says they're very much alike in this respect. In this cartridge that difference may be enough to mean that Re17 hits max pressure that bit quicker and so doesn't give any MV gain.

On the other hand, people are saying that the new Nitrochemie technology means you can't compare this powder to existing surface coated types. So, it's possible that QuickLOAD underestimates its potential performance, as the algorithms it uses don't suit the new powder's characteristics.

At the end of the day, QuicKLOAD is a computer model, not an infallible oracle (assuming there is any such thing anyway). Even with conventional powders, like most QuickLOAD users, I've found that some results are spot on, but other combinations can be out a fair bit - in either direction.

As always, the answer is to go out and experiment on the range and work loads up carefully looking for the classic pressure signs. It may be that Reloder 17 will give higher MVs in the cartridge - I'm hoping to find this out for myself in due course. But, that's part of the fun in handloading and shooting. I for one wouldn't like it if QuickLOAD gave all the answers - as a useful aid in sorting out starting loads, yes...........doing it all for me, no.

Laurie,
York, England

 

[Moderator]

I did a lot of work with QuickLoad, prior to writing the QL user guide for this site. Laurie makes a very good point about the fact that it is a computer simulation. Here is a real world example.

4-5 years ago, I'd say that 90% or more of shooters running long bullets in the 6BR were using Varget. I did some QL modeling and it appeared that RL15 would yield 40-70 fps more velocity at the same pressure, at least with long throats and heavy bullets. With those predictions in hand many of my 6BR shooter friends tested RL15 and found that QL was, indeed, correct -- RL15 DID give more velocity than Varget, sometimes enough to hit a higher accuracy node. That was a BIG DEAL. And now RL15 is probably more popular than Varget among the 600-yard Benchrest crowd.

Back to QL. When I ran the RL15 analysis I also "ran the numbers" for other powders. QL also predicted that IMR4895 would also yield similar velocity gains. Woohoo I thought -- that stuff is cheaper and easy to find. Well, guess what, when I did test IMR4895, it gave LESS velocity than Varget--and quite a bit less than RL15.

So. QL was right about RL15 which lead to some good changes. But QL was wrong about IMR4895, which lead to wasted components and range time. Ultimately you have to do real testing with real powders in real rifles.

 

[Steve Blair]

My modeling of RL17 mirrored our Moderator's work with RL15. Despite some reports that it was too slow and similar to 4350, QL predicted max pressures with an almost 100% full case and very good velocity. QL was correct and I was able to achieve 2979 fps from a 30" barrel in 95 degree temps. Testing again at 50-60 degrees demonstrated a drop of 113 fps to 2866. QuickLOAD did not predict that and shows one of this tool's limitations.

RL17 is still my choice for 6BR with Sierra 107s.

 

[Erik Cortina]

That's kind of what I was thinking, I've noticed that like you said, some are spot on and others appear to be pretty far off.

I'm preparing a ladder test for my 6.5X47 Lapua with 130 Berger VLD's as we speak, I'm going to see how good it will do with the VLD's. I have a load for the 129 SST with RL17 that really shoots, 1/4" MOA @ 100 yards 5 shot groups, awsome.

Thanks guys.

-Erik