Played with my 6.5 Grendel today using H322 and 123 Nosler CC's. Real life results at 26.6 gns gave me a muzzle velocity of 2433 FPS average. No ejector marks no pressure signs as far as primer protrusion. GRT has this over Pmax and over 2500 FPS. Backing off on GRT to 25.6 gns gives me FPS pretty much inline with real life. Is it safe to say that my pressure is more inline with GRT's 25.6 load?
Question about GRT ?
- Thread starter hounddawg
- Start date
What is GRT?
Just a quick look at my Hornady ref book I keep at the computer, 2350 FPS is max for 120-123 gr bullets (they used a semi auto and a 14.5 inch barrel)
As long as you don't have any of the pressure signs (including a sticky bolt) I would say your load is beyond that.
Unclenick will clear up the details but to go faster you have more pressure. It seems your gun can handle it fine.
But details missing on what GRT used vs your gun, barrel length.
Just a quick look at my Hornady ref book I keep at the computer, 2350 FPS is max for 120-123 gr bullets (they used a semi auto and a 14.5 inch barrel)
As long as you don't have any of the pressure signs (including a sticky bolt) I would say your load is beyond that.
Unclenick will clear up the details but to go faster you have more pressure. It seems your gun can handle it fine.
But details missing on what GRT used vs your gun, barrel length.
oh Sorry
GRT = Gordons reloading Tool
AR 15 , Sanders Armory upper with 20 inch barrel, Rock Creek match lower, Sig BDX scope @ 15X, Starline virgin brass, Fed AR primers, 26.6 gns H322, Nosler 123 CC's
According to Hodgdon load data FPS was dead nuts on. I had 2433 average, Hodgdon predicted 2434 for a 123 SMK. I have always found the Nosler CC's to be pretty much clones of the Sierras Weather was cold for here, 46.
Anyway I was just messing with GRT and Quickload after I got back playing with various powders in the programs and noticed that the data lined up pretty close in GRT for H322 if I took 1 grain off. Probably just an anomaly but thought it curious enough to post. I still am a babe in the woods with Quickload and GRT and trying to understand them
GRT = Gordons reloading Tool
AR 15 , Sanders Armory upper with 20 inch barrel, Rock Creek match lower, Sig BDX scope @ 15X, Starline virgin brass, Fed AR primers, 26.6 gns H322, Nosler 123 CC's
According to Hodgdon load data FPS was dead nuts on. I had 2433 average, Hodgdon predicted 2434 for a 123 SMK. I have always found the Nosler CC's to be pretty much clones of the Sierras Weather was cold for here, 46.
Anyway I was just messing with GRT and Quickload after I got back playing with various powders in the programs and noticed that the data lined up pretty close in GRT for H322 if I took 1 grain off. Probably just an anomaly but thought it curious enough to post. I still am a babe in the woods with Quickload and GRT and trying to understand them
CFE223
This is the first powder I've tried, which was highly recommended in the Alex. Arms Loading Manual. I settled on 30gr, giving over 2400 and 5 shot, .3" groups. That's right, three tenths! Hornady cases, 123SST, WSR. I have an Alexander Arms upper with an 18" Sanders Armory Barrel and Anderson Lower.
This is the first powder I've tried, which was highly recommended in the Alex. Arms Loading Manual. I settled on 30gr, giving over 2400 and 5 shot, .3" groups. That's right, three tenths! Hornady cases, 123SST, WSR. I have an Alexander Arms upper with an 18" Sanders Armory Barrel and Anderson Lower.
I re-ran your case on GRT with a few assumptions; , case capacity of 35.8 grain H2O, COAL 2.075", gas hole of 0.08" diameter at 14". I got MV of 2395fps and pressure of 51.9kpsi (12% below max). I think that's pretty close to your measured results, albeit a bit too warm to my liking.
Looks like H322 is a pretty good powder for 6.5mm grendel. Perhaps a bit on the fast side.
-TL
Sent from my SM-N960U using Tapatalk
Looks like H322 is a pretty good powder for 6.5mm grendel. Perhaps a bit on the fast side.
-TL
Sent from my SM-N960U using Tapatalk
Never been able to get this rifle below 1.0 MOA until lately it has been dipping under occasionally. The most likely reason is me, I have never really practiced with trying for precision with AR's that much. It could also be that this barrel is just coming into it's own. I had a Shilen .260 barrel on a bolt gun which was not worth a darn until it hit 400 rounds.
Yesterday was the best ever. I had a 4 round cloverleaf, then the 5th shot went a inch high then rounds 6 and 7 went back into the clover leaf for a six round .5 group with the H322. I think I will stick with the H322, I have 5 to 6 pounds of it on the shelf.
Yesterday was the best ever. I had a 4 round cloverleaf, then the 5th shot went a inch high then rounds 6 and 7 went back into the clover leaf for a six round .5 group with the H322. I think I will stick with the H322, I have 5 to 6 pounds of it on the shelf.
the Rock River is a match lower and has a nice 2 stage trigger. Thanks for the suggestion though.
I think the big issue was I had never thought about going backwards with bullet seating and always seated at manufacturers suggested length or in the case with Nosler who has no online data for the Grendel at 2.50 COAL or magazine length. I found my sweet spot at 2.38 by going in .003 at a time.
I was having a hard time adjusting the seating at the range because I had left my shell holder at home and it was cold and windy. As soon as I started seeing the groups tighten I stopped, packed up and came home. I was sitting a nickel on top of my ram and the round on the nickel, lol. It worked but the nickel kept falling off on the downstroke. Friday I am going back to verify (with a shell holder) at 850 yard if the wind/weaher/wife cooperates.
I think the big issue was I had never thought about going backwards with bullet seating and always seated at manufacturers suggested length or in the case with Nosler who has no online data for the Grendel at 2.50 COAL or magazine length. I found my sweet spot at 2.38 by going in .003 at a time.
I was having a hard time adjusting the seating at the range because I had left my shell holder at home and it was cold and windy. As soon as I started seeing the groups tighten I stopped, packed up and came home. I was sitting a nickel on top of my ram and the round on the nickel, lol. It worked but the nickel kept falling off on the downstroke. Friday I am going back to verify (with a shell holder) at 850 yard if the wind/weaher/wife cooperates.
A couple of first things to check:
Since cartridges that fire at over about 30,000 psi expand and stick to the chamber before the pressure peaks, you need to be sure you use the measured case water overflow capacity of as-fired brass from your chamber for either QL or GRT, as that is the volume that will affect peak pressure.
Most canister grade powders are held to ±3% of an optimum burn rate factor, Ba. So you need to adjust the burn rate up or down 6% to cover the possibility the burn rate used in the software is at one extreme and the lot you have is at the opposite extreme or somewhere in between.
Since cartridges that fire at over about 30,000 psi expand and stick to the chamber before the pressure peaks, you need to be sure you use the measured case water overflow capacity of as-fired brass from your chamber for either QL or GRT, as that is the volume that will affect peak pressure.
Most canister grade powders are held to ±3% of an optimum burn rate factor, Ba. So you need to adjust the burn rate up or down 6% to cover the possibility the burn rate used in the software is at one extreme and the lot you have is at the opposite extreme or somewhere in between.
3% of 26.6 is about .8 and GRT data lines up at 25.6 so that would make it close.
A side note is that I did not have my chrono at the range with me so I brought the Shotmarker to about 10 feet from the muzzle and fired three rounds to get the muzzle FPS. It should be quite accurate
A side note is that I did not have my chrono at the range with me so I brought the Shotmarker to about 10 feet from the muzzle and fired three rounds to get the muzzle FPS. It should be quite accurate
Cool! I'm about to get that tool for myself for Christmas.
Note that in QL when you select the output to be the incremental Loadtable (Icon of a square piece of paper with column lines and "+ –" at the bottom), "Options|Loadtable settings|Set burning rate variation" will let you select several fixed percentages. 5% is closest and what you want to look at.
Note that you can also tweak the weighting factor a bit and the start pressure a bit, as they are selected to be generally representative, but not specifically. A long tapered ogive, by the wedge principle, will see a bit less starting pressure required than a sharp one. Conversely, getting close to the throat raises it, per the QL instructions.
Note that in QL when you select the output to be the incremental Loadtable (Icon of a square piece of paper with column lines and "+ –" at the bottom), "Options|Loadtable settings|Set burning rate variation" will let you select several fixed percentages. 5% is closest and what you want to look at.
Note that you can also tweak the weighting factor a bit and the start pressure a bit, as they are selected to be generally representative, but not specifically. A long tapered ogive, by the wedge principle, will see a bit less starting pressure required than a sharp one. Conversely, getting close to the throat raises it, per the QL instructions.
I bet you will love that SM. before I had it I thought I will only use this for long range. Turns out it is great for load development since you can see the results immediately. Once you have the charge weight for a load you just load up 50 at that charge weight and at the longest COAL you are comfortable. Take a portable press and your calipers to the range, fire two or three rounds , adjust then fire two or three more till you get the group size you want. Resize what ever you have left of the fifty. No wasted components
