129 Grain Accubond LR Load Developement

[david7992]

I have the Howa mini as well and have been frustrated on finding a load. It actually shot the old recalled PPU 120's pretty well. I will try your load and see. Have you had any experiences using Alliant RL16 with the Grendel? Supposed to be the same a RL15 with a little more velocity. Works well in my 260.

[Schrambo]

Bakabone25-

Just yesterday... 18*, 46% RH, 4100' elevation, 12.5" BA barrel... I'll do a 5 shot group next...

12.5" BA barrel, Hornaday brass, 26.8gr 8208 (corrected!), CCI450 primer, COAL= 2.55", 129gr ABLR, just over 1" group... 200fps faster than my 11.5" Lilja, which was a surprise...

Series 61 Shots: 3
Min 2260 Max 2294
Avg 2274 S-D 17.4
ES 34

Series Shot Speed
61 1 2294 ft/s
61 2 2270 ft/s
61 3 2260 ft/s

[Mad Charlie]

When I was working up my load, it was in the low '90s, going to re shoot for chrono data soon, and get to the range with a few more different loads.

[bakabone25]

Bakabone25-

Just yesterday... 18*, 46% RH, 4100' elevation, 12.5" BA barrel... I'll do a 5 shot group next...

Hornaday brass, 27.8gr 8208, CCI450 primer, COAL= 2.55", 129gr ABLR, just over 1" group... 200fps faster than my 11.5" Lilja, which was a surprise...

Series 61 Shots: 3
Min 2260 Max 2294
Avg 2274 S-D 17.4
ES 34

Series Shot Speed
61 1 2294 ft/s
61 2 2270 ft/s
61 3 2260 ft/s

Thanks for that info Schrambo.
Today i ran some 129's from PF custom loads. Not very impressed actually. Average speed of 20 rounds measured with magnitospeed, was 2091 in the gb barrel. Bad part is the SD was 21.6. In my 18 odin works getting only average of 2149 and SD 28.8. So im thinking i will try loading some up also. Hell i dont think i can do worse. Part of the learning process. Ken

[grayfox]

I'll throw in $0.02... I had a bit of trouble getting a load I liked w/ the 129 ablr's so I tried the 129 sst's instead. They did well at 30.1/ 2415 ft/s/ 2.260" and single digit SD... from my 18" barrel (these loads are all cfe223). I have a decent ablr load for my 6.5 Howa 20" HB... 30.8/ 2440 ft/s and coal of 2.305", but the 130 AB (howa) at 30.8/ 2467/2.300" - that's what I'm using for the Howa.
Since the ablr works well in my creedmoor I'm not worried about using it in the Grrrs.

Now others on here do get good results with the ablr but I just wasn't satisfied in my AR.

[xlcc]

Here is some data I've collected over several range sessions last year. Shot from a 22" BHW barrel. The load is a 123gr A-Max over 31.2 grains of CFE, CCI 450 primer and a COAL of 2.250. The temp was taken from an airport about three miles from the range so take it for what it's worth. I allowed the ammo for 90 to 120 minutes to get near ambient air temp. Not exhaustive but I was just looking to get an idea. Sadly, I never did get to the range on a 70 degree day.

Temp Av Velocity
40 2497
50 2544
53 2548
56 2540
60 2581
80 2677
90 2661
90 2674

Wow,what a huge variation in velocity!

[Jakal]

27 grains of XBR runs the 129 ABLR at 2145 fps out of my Lilja 12.5" pistol. Anything over 27 felt like too much compression. I stayed at 27 grains as a MAX Load.

[bakabone25]

27 grains of XBR runs the 129 ABLR at 2145 fps out of my Lilja 12.5" pistol. Anything over 27 felt like too much compression. I stayed at 27 grains as a MAX Load.

Thanks Jakal, i will ladder up to 27 soon then. I will report back when i do.

[Schrambo]

27 grains of XBR runs the 129 ABLR at 2145 fps out of my Lilja 12.5" pistol. Anything over 27 felt like too much compression. I stayed at 27 grains as a MAX Load.

Thanks Jakal, my post was incorrect... I used 26.8gr of 8208, not 27.8gr...

[Bobke]

Couple of comments/questions, as I picked up several hundred factory seconds, with prospect of use in Grendel, 6.5x47 and Creedmoor. Found-and I shouldn’t have been surprised-variation on BTO length of .024 (.580 to .604), with largest portion between .598-.604. That said, if someone above was using seconds and didn’t sort, would kind of expect only fair accuracy. Other question-anyone try AR Comp or 2000MR with ABLR’s? ARC said to be slow but stable, and MR possibly slow and dense enough to get enough in a case to improve velocity. CFE has been my ‘go to’ powder with 120-123gr for last 4-5 years, loads developed in high temps, and now cool enough in TX that the variation might get me off a node. Hadn’t done enough chrono testing in cool weather to verify variance.

[Jakal]

I ran AR-COMP up to 27.5 grains. 1stCL: 26.6,26.9,27.2,27.5. 26.6 &27.5 shows promise, compression deforms bullet tip. No speed record, switched to XBR.

[RiverRider]

I have loaded up some 129 ABLRs with AR-Comp to try in the hopefully not-too-distant future.

I am relying on QuickLOAD for my experiments with AR-Comp since there is very little, if ANY, pressure tested and published data out there for this powder. In order to have any kind of idea what the pressures are, QL must be set up properly for the cartridge in question and that means entering case capacity, cartridge OAL, and adjustments for the particular lot of powder's burn rate, barrel length, and there are a couple of other small things to tweak. The end result is a chart which correlates charge with calculated pressure and velocity. When these loads are shot over a chronograph, a reasonable pressure estimate can be made---at least in theory.

Here is an example of QuickLOAD's output for 129 ABLR and AR-Comp (with certain information removed to reduce the clutter factor):

Cartridge          : 6.5 Grendel  (SAAMI)
Bullet             : .264, 129, Nosler AccuBond LR 58943
Useable Case Capaci: 28.910 grain H2O = 1.877 cm³
Cartridge O.A.L. L6: 2.260 inch = 57.40 mm
Barrel Length      : 15.5 inch = 393.7 mm
Powder             : Alliant AR-Comp

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-10.0   87    22.50   2045    1198   35733   8487     99.6    1.147
-09.0   88    22.75   2067    1223   36847   8555     99.7    1.133
-08.0   89    23.00   2088    1249   37994   8618     99.8    1.117
-07.0   90    23.25   2109    1274   39178   8677     99.9    1.100
-06.0   91    23.50   2130    1300   40401   8732    100.0    1.085
-05.0   92    23.75   2151    1326   41663   8783    100.0    1.069
-04.0   93    24.00   2172    1352   42968   8830    100.0    1.054
-03.0   94    24.25   2193    1378   44314   8875    100.0    1.039  
-02.0   95    24.50   2214    1404   45705   8920    100.0    1.025  
-01.0   96    24.75   2234    1430   47143   8965    100.0    1.011  
+00.0   97    25.00   2255    1456   48628   9009    100.0    0.997  
+01.0   98    25.25   2275    1483   50163   9052    100.0    0.983  
[b]+02.0   99    25.50   2296    1509   51750   9095    100.0    0.969[/b]  
+03.0  100    25.75   2316    1536   53392   9137    100.0    0.956  
+04.0  101    26.00   2336    1563   55090   9179    100.0    0.943  
+05.0  102    26.25   2356    1590   56846   9220    100.0    0.930  

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba     97    25.00   2339    1567   59701   8628    100.0    0.923  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     97    25.00   2125    1293   39079   9324     98.2    1.094

Now, if you look at the line which I made bold, you'll notice that the chamber pressure is very close to the SAAMI max of 52000 psi. This is what I look at...when I shoot my trial loads I will be watching velocities. As I progress and shoot the heavier loads, I will monitor velocity and once I see it approaching 2300 fps, I will discontinue the pressure trial. In this case, QL is predicting 2296 fps from a charge of 25.5 grains of AR-Comp. Depending on how well I've adjusted the burn rate factor and set other parameters, I may see 2300 fps at either a lower or higher charge. That does not concern me so much. What I can see is that it's going to take almost 52000 psi to reach 2300 fps in my rifle. You do NOT get free velocity, it always comes with a pressure price tag.

Without pressure measuring equipment, you do not KNOW what your pressures are...but this is a good way to approximate it. That's a hell of a lot better then watching for flattened primers (which is not a reliable method of estimating pressure until things get pretty extreme), measuring case head expansion (which is unreliable at best), and hoping your rifle doesn't decide to disincorporate. Even with published data, you may be led down the path into dangerous territory. More knowledgeable folks than I say that by the time you get visible pressure signs on your brass, pressures are already at 70 kpsi or more. The best estimate you're going to get without actually measuring pressure is a GOOD velocity reading.

[Jakal]

QL is the one tool I don't have. I did invest in a LabRadar and it was well worth every penny paid.

I would like to know the software tweaks being ran for the 6.5 Grendel, as some say that QL is not set up correctly for the Grendel.

Being an "estimating" software, I can see where it would be helpful for load development, if the parameters are known and correct. QL has the same problem with the 458 Socom.

[RiverRider]

I've also been told QL is inaccurate for the Grendel and asked for further explanation, but got no response. I'm having to feel my way along with it...I did acquire a pound of 8208XBR and there's published data for that, so maybe I'll be able to make meaningful comparisons between published data and QL predictions.

There is ONE parameter in QL I have never been too sure about, it is the Weighting Factor. It is user adjustable but the field has a default value in it for each cartridge. It represents the percentage of the powder charge that wads up behind the bullet and attempts to follow it down the bore. I suspect this might be the fly in the ointment for the Grendel, but that's just a guess on my part. I've questioned many of the Weighting Factor defaults in QL...and I've played with the values for some cartridges and found that it makes a significant difference.

I can say that QL is pretty darned accurate for many cartridges. I've been using it for six or seven years now, I think, and it has proven to be a great tool. I'd urge you to get it if you do lots of handloading with a variety of cartridges. I would guess that you do, seeing that you opted for the LabRadar...that's top drawer equipment. I'm using a Oehler 35P these days and I believe it's reliable enough for my purposes.

[LRRPF52]

8208 XBR and AR Comp are a bit on the fast side even for 120gr projectiles in 6.5 Grendel, although very popular with 120 and 123gr loads, as long as you don't exceed 28.5gr with a 123gr cup and core bullet like the 123gr SMK or 123gr Scenar.

With 100gr bullets, you will fill the case before you hit 50ksi, and you can reference this in Hodgdon's data, which is included in both Volume I and Volume II of the 6.5 Grendel Handbooks.

I personally would only use 8208 XBR or AR Comp with the 129gr ABLR if I really want super tight ES for some reason, otherwise just use CFE223 or LVR for speed, or step down to AA2520, BL-C(2).

To me, CFE223 does what BL-C(2) and AA2520 never could.

Since the 129gr ABLR has such excellent expansion characteristics, retains velocity extremely well with its .553 G1 BC (Litz), it doesn't matter too much what speed you launch it at, because it will fully expand within the first inch or two of penetration, and continue to plow through tissue with minimal weight shed since it's bonded.