New grendel build

[6BRshooter]

Well I am waiting for a CSS/LW barrel, should be here in a couple weeks. It is a 22" target crown bull, I plan on putting it on a DPMS 7075 lo-pro with a standard FF tube. The lower is a bushy with JP trigger and A2 stock. It normally has a 16" varmint 223 upper on it, bone stock DPMS that with my 50 vmax loads shoots honest 1/2moa AVEs. The LW barrel was delayed so I decided to order a shorter barrel from midway, one of their AR Stoner 18"spr profile. Showed available sunday night, monday AM called midway, out of stock till feb. Thought some more on it and decided that the 16"M4 profile would work and probably make more sense because of the 22" inbound. Midway description stated carbine gas length and M4 profile 6.5gendel chamber, 1-8 SS. The barrel that showed up was a 16" mid-length 1-8 SS in 264LBC, the profile was .850"UTG; .750"GB; .740" to FH. Fine by me I prefered the mid-length and the contour. It went on another lo-pro receiver I had and I used aYHM lo-profile gb to fit under the rifle length FF tube. Capped it off with an A2 FH. I used blue loctite on the barrel extension and gb to bed them and torqued the barrel nut to 60 twice and then aligned for gas tube.

I had loaded up some match prepped hornady brass with CCI BR-4 and varget in charges of 28-29 in .2 increments and 123NCC. I set OAL from ogive to 1.870", just .015 less then mag-length. I figured I would still be jumping them. When I got the barrel in I dropped a rd in and tried to close the bolt, wouldn't go.:confused: I then went to extract the rd and pulled the bullet out and dumped powder on the kitchen floor. I used my horn bullet jam finder and found out that with that bullet and this chamber OAL from ogive needed to be 1.700" or less. Easily fits in a mag at that length. I pushed all the bullets in with forster Ultra seater to be .010 off, I have found that most SMK/NCC like to be .020-.010 off the lands.

Finally shot it today with a 6.5-20vortex viper in a PEPR mount. That optic will probably ride on the LW barreled upper. I shot prone from a bipod, it was 24*F, I had a flier in a couple groups that turned them from 1/2moa to 1-1.25moa. The 28.0 load was good (4rds in a .7" with 5rds making it 1.25) showed a little vertical, coulda been me, the 28.2 was real nice (4 in .4" with 5 in .75), showed horizontal from wind, and the 29.0 was in the .6s when done. The 29.0 gr load was only 4 shot as the powder spill was from that charge group.

I need to figure out a good scope for this rig. Thinking a 3-9 or 2.5-10. Really tore between a vx-r patrol or a 2.5-10 viper HS or PST. I think the PST MOA reticle and the TMR in the Loopy are probably more useable. I plan to load up some more tonight and maybe chrono tomorrow and shoot some more groups of the 29.0 and 28.2.

Any other good bullets to try, thinking 600yd and under for yote rig and steel, with shorter distance for deer pest permit use in summer over bean fields.

[bwaites]

Cant get enough Varget in there to get good velocity. Try some BLc-2 (dirty) or XBR 8208, TAC, or 2520.

Nice accuracy though!

[Whelenon]

I got sub-moa 5-shot @ 100yds with 28.8g of Varget, & Sierra 120 Pro-Hunter, don't know the FPS. Shooting Varget because that's what I had on hand. My next recipe I want to try 8280 as bwaites and many others have recommended.

[6BRshooter]

I never had much luck with the 8208. I am trying to use what I have on hand before I go and buy a different powder. I got H4831sc, way too slow; varget and H4895, all in 8lbs jugs. I do have some BL-C2, I never thought it was too dirty just temp sensitve. Benchmark and Reloader 10x. Of these which would you try4895, bl-c2 or buy a different powder... I think I will load up just 5 rds of of the 29 and 28.2 varget just to see what they do over a chrono. They did seem mild as far as recoil and the primers did not have that hot look to them. The 29 gr load actually crunched when I seated the bullet, I imagine I am running out of case capacity before I am getting the pressure up to make velocity. I am looking for 2300-2400 fps in this load, more is better though, what powder is my best bet. You guys have a lot more experience with this cartridge then me, thanks.

[bwaites]

Of those, BLC-2 will give good velocities with 120-123's. Benchmark works pretty well with lighter bullets. Reloder 10 is asking for problems. It acts really strange in the Grendel, very unpredictable pressures.

[6BRshooter]

Is H4895 to slow also? It is faster then varget and usually gives a little more speed then varget in my 223 and 308 loads. I might just have to blow the dust of the bl-c2 and try it. Is tac fairly temp insensitive?

[bwaites]

Is H4895 to slow also? It is faster then varget and usually gives a little more speed then varget in my 223 and 308 loads. I might just have to blow the dust of the bl-c2 and try it. Is tac fairly temp insensitive?

The small Grendel case usually doesn't allow enough of the extruded powders to get good pressure and velocity curves. XBR tends to be the exception, because it such a tiny grain.

TAC can be temp sensitive, so caution with it and 2520 must be considered. Sensitivity is why so many of us have switched to XBR.

[6BRshooter]

My 223 AR load that is 1/2moa is using BL-c2. I just have to rezero when there is 40-50* temp changes (usually summer and winter). The drop does not seem to change just initial POI. Once that is adjusted for the drop is the same. I will try BL-C2 and maybe look into 8208 again. I could not get it (8208) to work worth a darn in a 6br rifle, switched to 10x and it shoots in the .1s with 66 barts.

[bwaites]

That the same experience I had with Reloder 17 in my 7mm WSM. It shot H1000 into bugholes, but RE 17 a little faster but in a shotgun pattern. Went back to H1000.

[6BRshooter]

Well i chronoed a few loads: 29.0varg was 2359 sd of 9.97, 31.5 blc2 was 2365 sd of 18, 31.8 blc2 was 2406sd of 15. Did not have a
chance to shoot groups with the blc2

[bwaites]

Compressed Varget scares me, but I'm a wimp when it comes to explosions inches from my face!

Interesting that you were only seeing a little more velocity out of BLC2, which really makes me wonder what the pressures on that compressed Varget might be!

[stokesrj]

Bill,
You gotta toughen up, Varget is one of the most popular powders used in High Power competition for Service rifles. A standard .223 load is 24.5 grains behind a 77 SMK and it takes a lot of crunching to get that bullet seated. But there are hundreds of thousands of rounds of this load fired each year without incident.
Bob

[6BRshooter]

I can tell yoh the primers were flattened more on the blc2 loads. On the varget loads the primers still had a round edge to them. Case growth was nil and the web had not grown any. This lot of varget is slower then the previous lot by 50fps in my 308 loads at the same powder charge.

[bwaites]

Bill,
You gotta toughen up, Varget is one of the most popular powders used in High Power competition for Service rifles. A standard .223 load is 24.5 grains behind a 77 SMK and it takes a lot of crunching to get that bullet seated. But there are hundreds of thousands of rounds of this load fired each year without incident.
Bob

I know, I know......I love Varget in the .308 loads I've used it in, and its the hot ticket in F T/R. But compressed loads just seem strange to me!

I had a kaboom last summer with TAC in a load that wasn't particularly hot in cool weather but too hot in warm weather, and now I'm even more shy!

[Variable]

I had a kaboom last summer with TAC in a load that wasn't particularly hot in cool weather but too hot in warm weather, and now I'm even more shy!

Details??? Pics???

[bwaites]

Details??? Pics???

It was a 5.56 load. I posted it on the old forum, so it was actually Summer 2010. Here's the pics.









If I remember correctly, it was a 69 Sierra over 24.3 grains of TAC in a 1:7 barrel.

[Deezil]

varget has never worked well for me, so Ive stayed away, but I did load some compressed .223 stuff when I was playing with it, just doesnt seem right to be jamming it in there like that, but the good news is its hard to put too much in!

[Variable]

It was a 5.56 load. I posted it on the old forum, so it was actually Summer 2010. Here's the pics.

Ouch. Any damage to your upper?

[mwilkins]

Yep, think I would have to go check my britches after that one. Hopefully no damage to your gun.

[bwaites]

None I can find, cleaned it up, and it shot fine.

I love the way AR's make belted cartridges out of high pressure rounds, though! LOL


OP, sorry for the thread hijack!!

Everyone, back to the regularly scheduled programming, the OP has a new build to talk about!!