Reloader 15.5. Has anyone tried this powder?

[Tangodown]

Finally finished my 6mm Arc build……and yes I’m new here so I figured I’d join up if I’m becoming part of the 6mm Arc family

Mega upper/lower
18” SS Proof 
Seeking precision adjustable gas block
CMC 2 stage
JP bolt and carrier

Looking at reloading data and can only find Hornady published loads.

I’ve never handloaded for a gas gun

But I have 3 decades of handloading experience in bolt action rifles 

Question:  has anyone tried Reloader 15.5 powder.  I’m hearing it’s very temp intensive and it falls in between:

CFE 223 and Leverevolution

I’m looking to develop a deer hunting load and target load 
Both these powders give the best velocities. But are not known for temperature stability. It seems Reloader 15.5 might be ideal for speed and temp stability. 

Leaning towards 3 billets for hunting:

90 grain Nosler accubond
95 grain Nosler BT
103 grain Hornady ELDX

For target I haven’t decided but something from Berger or Sierra with high BC

[UncleBob]

Welcome, and nice setup. I don't have any experience with 15.5. My experience has been the sweetspot for the ARC seems to be 75-90gr range. 15.5 should work very well. The two powders I've had great success with are Accurate 2495 and VihtaVouri N135. I had some great velocities and consistency out of N135 with 87gr VMAX.
My Quickload says running 90gr Accubond 28.7gr of 15.5 should get you about 2800FPS or thereabouts. That is with 107% (compressed) fill and just under 51kpsi of pressure. I am not a fan of 103ELDXs, I can't get them going fast enough for my liking. Hope this helps.
Have fun with it, and shoot happy.

[Tangodown]

Thank you!

Quickload is one thing I don’t have. I think it’s on my to get list soon.

[alwie]

xxl-reloading.com gives a range for the 103 eld-x —  using Reloader  TS15.5  The interesting thing is that for 6 ARC there is not much difference using TS 15 vs TS 15.5.

Actual give info for TS 15.5

Load.                        press.         

Min:22.2gr — 81.0%  32866 -– 63%

Max:25.6gr — 93.2%  45629 – 88%

[Tangodown]

Interesting. I’ve handloaded for mostly wildcats

6mm AI is my most recent coyote gun. Typically a lot of interpolation off of 6mm REM data in load manuals. I usually cross check with 6mm-284 load data …..example would be if 6mm AI is 9.6% more case capacity I will start with 6mm REM max load and more up slowly to about 9% over that. But if I check 6mm-284 load data and if at any point I’m above published 6mm-284 data I know I’m probably too high for 6mm AI and just won’t go there.

Chronograph and brass inspection after each shot will tell me a lot. I’ve learned not to push the envelope and pay attention. An extra 50 FPS isn’t worth the danger.

I’ve done this with bolt guns

This is my first gasser i will be reloading for.

I really prefer temp stable powders…..I’m kinda OCD like that. I just noticed 15.5 falls between CCE and LVR.

But powders do what powders do

[grayfox]

Welcome aboard Tango. First thing to be aware of, is the 6mm ARC and the 6.5 Grendel do not show brass marks until way over-pressure, since they are (for ARs) 52000 psi Saami limit rounds.
So you can't go by the old standby of if there are no marks, then I'm not over-pressure.

As to RL 15.5, I'm in a wait and see, RL15 and Varget are both listed in Hornady data but you don't get a lot of MV for the heavier bullets. I've got some loads that are ok for 100 gr in Varget, but in general those are for bolt action where the Saami is 62Ksi -- not that I have to go 'way up close to that.
Burn rate does not tell the whole story when it comes to Lever and CFE, those 2 powders have a markedly different, and more rounded, pressure curve than other powders, which is why, peak psi to peak psi, you get more MV out of them (MV is proportional to the area under the Pressure curve, not, strictly speaking, to the peak itself).
Now 15.5 may have that same rounded psi characteristic as CFE/Lvr, but I have not seen this documented or discussed anywhere. So, wait and see. OTOH, for Grendel several of us have found that AR Comp, which is not a documented powder, works very well for the 120 class 6.5 bullets in the Grrr... so 15.5 may indeed turn out to be that kind of powder for the Arc.

The other useful tool(s) are Quickload or Grt, but again, for the short cartridges like Grendel/ARC, these 2 apps need some tuning to be truly representative... there are lots of discussions on 65Grendel.com about this by guys who were in on some of the first testing, I myself have found it to be true for Grt, but have not devoted the time/effort to QL. So it can be useful but according to those guys, they take more tweaking than most cartridges.

The mostly go-to powders for the Arc are pretty much the ball powders like Lvr and CFE, with AA2520 right in there. I've seen some drop in MV per temperature, from CFE and Lvr but not to the extent that "charts" say they should... 'course I'm new to that MV-temp measuring game, so I can't draw conclusions on them one way or the other.

Anyway, will be interested on what y'all find out about 15.5 in the Arc, we're always open to learn something!

[Tangodown]

Thank you so much for that info

Very very helpful!!!

Interesting enough…..my LGS had ARComp and Reloader 16 in stock.  They are both part of the TS line of Alliant powders.

So I grabbed a pound of each.  I’ve read a little about ARComp in the 6mm Arc and I’ve wanted to try RL16 in My 30-06 as it’s right next to my go to powder H4350

I know what you mean by how a powder behaves in one cartridge to the next. I know guys who swear by H4350 in the 6mm AI…..I had it “spike” early on me when testing loads with 87 and 75 Vmaxs……I found that slower powders gave me better velocity and better accuracy. My Pacnor 28” barrel shoots 1/3 MOA with N160 and Hybrid100V.

[tpepper70]

I'm curious to see the results you have with AR Comp. I have a bunch from my Grendel days. Please keep us posted.