6.5 Grendel hunting

[Huntchic]

Ill start with im not sure if i should be posting here or under deer hunting.
I hunt whitetail in a couple different states north and south. I hunt a good bit around fields surrounded by very thick brush n briers so use shoulder and neck shots for DRT. I tracked one deer i shot behind shoulder with muzzle loader for 100 yards and it took 4 hours to get in and it out crawling n cussing so after that i shot everything in the neck or shoulder with the muzzleloader. for rife I've been using 30-06. with 165 partition for past great many years.
I just built an AR in 6.5 Grendel with 18" Barrel with the thought of a lighter more handy rifle for backpack hunting and just in general. I chose 3 bullets to load for it. 123 ELD match, 123 SST and 125 Partition. all three bullets have same POI to 100 yard. Im using TAC and CFE223 powders. I load for a number of handguns and rifles so want to stick with CFE or Tac to not add another powder into my loading.
I developed a excellent accuracy load of CFE around 30.2 (touching) a good accuracy load at 31.2 ( Just at 1MOA). I went up to 31.5 and got good accuracy there also ( .75 MOA) but based on Hornady data 3.2 is max for CFE so I didn't choose that loading even though Hornady shows like 31.7 for 129 grain bullets and 31.2 for 123 grain bullets. Go figure ???
With TAC im shooting 27.9 with extremely good accuracy also.
Now without a chronograph ( don't ask. LOL) I'm estimating from 18" Barrel 125 and 123 bullets at 30.2 around 2420 FPS,
31.2 around 2500 fps. 27.9 of TAC around 2410fps.
I've heard n read CFE223 is temp sensitive and Tac is less sensitive than CFE so that's why i developed the TAC load. i developed these loads at 80 degrees. i normally hunt in places from 70 degrees to 15 degrees. also why i didn't go with the CFE load at 31.5 gr. for fear of it being over pressure at 90 degrees.
So now my questions.
Are my velocity estimate about right in 18" barrel?

Do i need to be afraid of using a 31.5 of CFE powder or CFE in any loadings do to temp changes ?

Would i be better off with using TAC even though is a bit slower velocity but would it be better/ safer in warmer and colder weather?
Will a 125 Partition get complete pass through on shoulder shots at like 150 or less with muzzle velocity at 2400 ?
Over 150 would be neck shots with the 125 sst around 2450-2500fps is the plan. I don't plan to shoot beyond 300-350 yards with the Grendel.

 

[MThuntr]

Load development at 80 likely won't have issue at 90. I'd be concerned if your ammo was baking in the truck at 120 degrees. That's where you'll get loads to spike. You're not gaining much by pushing pressure in the Grendel so if you're 90 fps slower you're not going to notice that at any distance especially if you're proficient at shooting

I've killed deer to 250 with 123SST out of my Grendel (velocity is mid 2400s) clean pass throughs and good expansion from just behind the shoulder. Performance of that bullet has been nothing but exceptional for me. I'd assume the Partition will do as good.

See if you can track down a chronograph to borrow. You may even be able to snag a used magneto speed or labradar for cheap ever since the onboarding of the Garmin and soon to be others using similar tech.

 

[Huntchic]

I appreciate that input MThunter,
I’ve shot deer with 222 Remington, 5.56, 243 and other larger calibers over the years but I’m unfamiliar with the Grendel but for whatever reasons decided to give it a go. Figured it would serve well as a deer rifle but could also provide camp security while in backwoods.
Anyhow my main concerns were CFE n temperature affects down around 15 ish to like 90.
I have been hunting 2 large old fields a lot where not having them run into the brush around the fields is a priority. Lol

 

[Huntchic]

I was shooting handguns few weeks ago and yeah it got nailed. DRT shot. Friends shouldn't let friends shoot over there crono. LOL.
Im going to replace it soon.
some of my actual starting test with Grendel was over the crono.
Yep a magneto is going to be my purchase. I rarely need to test handguns so think its the way to go too.
was testing some 10mm and 454 Casul when it got nailed.

 

[Okie_Poke]

In my old Grendel barrel (16" Alexander Arms lightweight), my load for every 123 grain bullet was 31.0 grains of CFE 223. Velocity was around 2450 for each of them, and they all shot to the same basic POI at 100 yards. I ran that load from winter to summer in Oklahoma without incident. I backed off a bit more (30.5 gr) when I was reloading on a progressive press just so I didn't have to worry about it, even though CFE meters very well.

The velocity is going to vary a little bit from summer to winter, but it wasn't enough to really matter to me for the type of hunting I do with the Grendel. While definitely not a temp insensitive powder, CFE 223 is not THAT temp sensitive.

I don't see a need to push an 18" Grendel to 2500 fps for hunting. It's just not a long range game killer, and the extra few fps doesn't really matter much. If you can get that velocity comfortably, great, but otherwise back off a bit and use one of the lower loads and just don't worry about it.

I never shot the 125 partition, but I don't see why it wouldn't work just fine. Note, however, that at Grendel velocities the 123 SST isn't grenading like those bullets tend to do at 3000 fps. My experience with the 123 SST is similar to MThuntr's. I'd settle on whichever bullet shoots better (or good enough and you can get it consistently), and just shoot that one. For me, that was 123 SST and 123 ELDM (after it replaced 123 BTHP).

I didn't give up on the cartridge or anything. I have a new Grendel barrel (18" X-Caliber SPR contour), but it doesn't like CFE 223 very much for reasons I can't explain. Infuriating, really.

 

[Huntchic]

That’s great information and very helpful.
Thanks Okie-Poke !
I have to say my load with 30.3 CFE and SST 123 , 123 ElDM as well as the 125 partition shoot touching each other reliably. Figured it was right around 2400 fps. I shot a bunch in the 30.9 to 31.3 range but all seemed to be at 1” groups. Just couldn’t find the tight .5 group I really wanted in that area of loading. At few I shot at 31.5 were nice group but was bit nervous at the 31.5 and hearing CFE was possibly could spike.
Yourself and MThunter both told me not to be concerned about 80-90 fps. 2400 fps vs 2500 fps just didn’t make much difference.
Right now I’m running with the 30.3 load because it’s so accurate. Im going to keep playing some around the 31.0 area looking for better accuracy. Im using 2.250 COL with SST and 2.240 with partition. Going to try different COL’s and mess with crimp some also to see if I can get a happy place.

 

[Huntchic]

Okie-Poke,
I know I’ve heard a few times that some barrels didn’t like CFE223 powder from others. I had excellent accuracy out of TAC powder at 27.8 which should be around the 2400 fps in 18” barrel.
I have had good success using TAC in other cartridges. Once I replace my dead Crono I may go with TAC instead of CFE if I can get it over 2400fps

 

[Okie_Poke]

I shot a bunch in the 30.9 to 31.3 range but all seemed to be at 1” groups. Just couldn’t find the tight .5 group I really wanted in that area of loading.

I'm going to be honest, I've never had a rifle that consistently shot 0.5" groups at 100 yards, particularly not an AR. I know other folks have had different experiences than me, and I don't have any high-end or custom rifles, but I wouldn't judge my load by whether it can print 1/2 MOA groups or not from an AR. I've certainly shot 1/2 MOA groups before, but even my bolt guns don't do that on average with their favorite loads. If you are consistently getting that tight of accuracy, great---stop fiddling with the load and go with that.

Right now I’m running with the 30.3 load because it’s so accurate. Im going to keep playing some around the 31.0 area looking for better accuracy. Im using 2.250 COL with SST and 2.240 with partition. Going to try different COL’s and mess with crimp some also to see if I can get a happy place.

Somewhat related to the above, I think most of this fiddling will just waste components. Please, feel free to test all of this out for yourself and see if you can find the perfect load. Sometimes fiddling with a load is a fun end in it's own right. But I'd just set the bullet 0.020" to 0.030" off the lands and be done with it, assuming that's (i) under mag length and (ii) doesn't push the bullet too far into the case. Without measuring the max COAL for your chamber with your bullets, I can't tell you whether your stated COALs will work or not. If you can't measure where the lands are, just use the book COALs. I don't bother crimping my AR food anymore either as I've never had a problem with the bullets moving under recoil without the crimp.

You didn't really ask, but here's my suggestion: load 10 rounds each at 30.3 grains and 30.8 grains with one particular bullet, using the book COAL for that bullet. Load up both powder charges for both bullets if you'd like. Shoot at 100 yards. You can shoot 3 or 5 and rest the barrel to cool down if you want, but shoot all 10 of each loading at the same POI. Use your best supported benchrest technique; you do not get to disqualify any "fliers" from this exercise. If you can do this over a chronograph, all the better.

My suspicion is that your groups using the same bullet will be approximatley the same size. If one group is drastically better than the other(s), then maybe that load is actually better, but that result would surprise me. Pick whichever load you feel better about, or that gives you the velocity you want, and be happy.

You can fiddle with load development as much as you want, but often you're better off stopping when you get to "good enough" and using the saved components for practicing with that load. Small changes to a load usually do not result in large changes in accuracy over the long run.

 

[Huntchic]

I agree with everything you said. Yes I get enjoyment from trying to get best I can from each loading. With Grendel I did same process as I’ve always used with other new rifles, barrels or calibers. Pick a load around 1/3 way up in the book data or low end of velocity I’m hoping for. Make n measure dummy round to find lands. Then load 5 rounds at .3 grain increments to near or at max data using book COL. See where best 5 groupings are. Then I load 5 more at previous load group plus 5 at .2 bellow and .2 above that amount that gave me good group initially. Go with whatever amount gave best grouping. Then depending on calculating my distance to lands my change Col a little or just stay with load data COL. With CFE and 123 SST all shots using my method seems to be same group size at 30.9 to 31.3 slightly better at the 31.3 so that’s where I settled at. I did try 3.5 and got a nice group at about 5/8 inches. However hornady max load is 31.2 so decided to stay at the 31.3 load.
Crazy thing is the hornady manual shows max load with 123 grain bullets at 31.2 yet with 129 and 130 grain bullets they show max load at 31.7 of CFE.
Just not sure if using the 31.5 would be safe or not and considering possibility of temperature changes Will just stick with loads at 30.3 and 31.3.

 

[hunting1]

I use TAC with 120 gr NBT and W748 with 123SST's. CFE223 gives the highest velocity but poor accuracy as well RL15 and H335 did not group well for me.

 

[Huntchic]

Well i also came up with a load using TAC around 2400fps with 123 SST and 125 partitions. Excellent accuracy. Like you I got higher velocities using CFE223 but I got good accuracy with it at 30.2 and up at 31.5 but the 31.5 was over listed max for 123’s at 31.2. I got decent accuracy around 31 but only 1 moa. I prefer loads that are .5 or touching.
1 moa at 300 yards is 3” plus any wind or other effects so I’m not really happy at Moa.

 

[Huntchic]

In the beginnings I knew I would use 125 partition and labored over a second bullet. I considered the 120 pro hunter, Nosler ballistic tip and even the 129 interlock but ruled out the 129 because of its weight, ballistics and speed. I liked that lots of folks said the pro hunter with flat base was really accurate but again it’s ballistics couldn’t match the SST. The ballistic tip I ruled out due to cost and it also didn’t quite have the BC of a SST. Plus I can pretty much always find Hornady and at times Nosler can be hard to find.
I’m solid on the partitions for hunting but still not sure if SST or ELD match is better for deer. Both shoot exactly same in my rifle accuracy wise but went SST because its slightly better BC plus it is an interlock with a polymer tip. Always did well with regular soft point interlocks in other calibers thus went with the SST.
Been trying to stay with powders Im happy with and use in other calibers like TAC but did get CFE223 for Grendel because it can give higher velocities. I love TAC in a few calibers including Grendel for its accuracy and better stability in temperatures. It just can’t give the velocity CFE does. I plan to try TAC vs CFE223 loads when temperatures hit 90’s and in temperatures around 15-20. Want to see velocity changes and how much if any poi shifts or group changes. Right now Im thinking CFE loads in early season hunting down to around 40 the under 40 or above 80 using TAC loads. However using TAC loads at 2400 fps in 80 degrees may make sense to just use TAC year round if it does well in all temps and CFE shows any issues.

 

[Huntchic]

As Okie Poke was saying about fiddling with loading. For me it’s relaxing. It’s kinda like cooking in a way. Trying to come up with that perfect mix of ingredients. I’m a science gal and outdoors person as well as huntress so for me handloading just fits and find it satisfying.