6.5 Grendel HUGE bullet runout. NEED HELP.

[EvilRoy]

Hello everyone, this is my first time to post here. I am having a very hard time getting bullets seated for my 6.5 grendel. Currently, I have tried Hornady case (reloads) and new Lapua brass both yielding similar results. Both cases are giving 0.005-0.015 bullet runout as measured from the front of the ogive. I have also measured towards the rear of the ogive with excessive runout as well although it is smaller. I feel that my bullets are tipping in some way. My loading equipment for the Grendel is: Forster coax press, Redding S bushing full length resize die, Century mandrel die (expands to give 1 1/2 thousandths neck tension) htand a Forster Ultra micrometer seating die. I am doing full brass prep including turning case necks. Even though I am doing the things I know should be done, I am getting runout values as I previously stated. I am fairly certain that my brass prep and process is not the cause of such large runout measurement ( measuring with 21st Century comparator with wheel). I can say I'm certain about my process because, I also am reloading 308 and concistantly getting 0.0005-0.0015 bullet runout. Both 308 and 6.5 Grendel are using Hornady ELD-M bullets. I had suspected the Forster seating die may have been defective on seating stem alignment or the bullet tip was bottoming out in the seating stem, but when I used my Wilson chamber die, I got similar results. I have measured my brass from top to bottom and the case concentricity is near perfect. So, any ideas what could be going on of something I am not thinking about. I can't figure out how the same process with 6.5 and 308 would yield such different results. I have tried full prep and no prep using the new Lapua brass with dry neck lube during seating and no big changes. I could really use some fresh ideas because I am out of them.

Thanks
Roy H.

 

[NZ_Fclass]

Seems unusual...how about the concentricity of the inside of the case neck?
Why are you neck turning the Grendel - custom chamber or factory rifle?

 

[EvilRoy]

Seems unusual...how about the concentricity of the inside of the case neck?
Why are you neck turning the Grendel - custom chamber or factory rifle?

Measurements of the case neck is internally is 0.0005-0.001. I am turning brass to get my routine down and make what I do better before I jump in feet first into F or FTR class shooting. It's been awhile since I have run target ammo. Now when I actually get set for it I will have dies made to fit my chamber more or less. The Grendel rifle is an AR but it likes the factory Hornady 123 GR ELD/M ammo will do 1/2 moa if I do what I am supposed to do. Figured I try to shave a bit more off my group with handloads. Problem is I can't understand the difference between the Grendel and the 308 when I do the same thing to both rounds. 308 good and the Grendel is bad. I wonder if the bushing is causing issues. My 308 has the non-micrometer Forster NM FL resize and seating die set and the Grendel has the Redding type S bushing die and Forster micrometer seating die. Wonder if the bushing is the issue. That's really the only other thing that is different between the two sets of dies. Otherwise I might get a neck reamer and clean up the case a bit more (but very gently) . That's the only other choice I have available, that I personally can think of. Surely someone on here have seen this particular oddity and might lead me to something I'm not thinking about or might have missed.

 

[Sniper338]

Are you running the brass over the 6.5 mandrel before you neck turn? Neck turn mandrel is the same size as the 6.5 expand mandrel?

Is this before or after fireforming/1 round on the case fired?

 

[EvilRoy]

Are you running the brass over the 6.5 mandrel before you neck turn? Neck turn mandrel is the same size as the 6.5 expand mandrel?

Is this before or after fireforming/1 round on the case fired?

Yes I resize, then run through expander mandrel before I neck turn. Once done turning resize again do the remaining case prep ultimately leading to seating bullet. Something in the seating process is killing the concentricity. I'm even dry lubing inside the case neck to try and help the seating along.

 

[Sniper338]

Yes I resize, then run through expander mandrel before I neck turn. Once done turning resize again do the remaining case prep ultimately leading to seating bullet. Something in the seating process is killing the concentricity. I'm even dry lubing inside the case neck to try and help the seating along.

Do you have the expander mandrel stem out of the sizing die?

 

[Sniper338]

I dont use a press for seating. But when I did I turned the round about 4 times while seating. Seat alittle, turn, seat alittle, turn, seat alittle, turn until bullet was seated all the way.

Ive never used forester anything so I dont know about those dies. I use hand dies and an arbor press for seating.

In the expanding die, are you taking the brass neck all the way up the arbor? It only needs to go up about half way on the arbor.

You need to test and isolate the problem in your process. After expanding necks, check for consentricty.

Try a different bullet. Could be the bullets arent great. Hornandy elds are the worst hornady bullet ive used personally. Im still sitting on a pile of 123 amax for my grendel.

 

[NZ_Fclass]

I use the Forster die for sizing 308 too. And the seater. No problems, once I fixed the seating stem - polished and straightened. You dont say what size bushing you are using, and the final neck size. But if you have checked case concentricity after prep..neck and body?. Is the neck tension sufficient for an AR?

I dont do half the prep that you are doing - and I use Hornady and Lapua cases in a factory Howa and have no run out issues, maybe a thou or two - but it doesn't affect accuracy. I have the Redding 3 die set, no bushing, but an expander mandrel. I don't neck turn, as it's a factory chamber. Hornady cases when the grandson is shooting it, Lapua when I use it, which is rare these days, with the shortages of Lapua and Sierra pills down here - most bullets are short right now and 6.5s are unicorns.

Try Lapua or Sierra bullets, see if the problem goes away.

 

[PRR1957]

I use the Redding neck bushing resizing dies in both full length and neck for six different cartridges, and what I found is to screw down bushing retainer screw until it stops on the neck bushing, then back the screw off by 1/16 of a turn to allow the bushing to float, which allows the bushing to self centered on the case neck. I also lube the top of the bushing rim and bottom of the bushing retainer screw with graphite powder. Cartridge case neck runout is usually no more then .0003”-.0006” without or with a bullet seated.

Also. The choice of Hornady bullets is always suspect in that their bullet along with Speer, Sierra, and Nosler bullets are not true match bullets. At least in my opinion. There are many small variations that occurs during the manufacturing process. Sierra at times holds a higher production standard for their match grade bullets, but can vary from one production lot to next production lot. The thing to consider is the bullets are made on production machines with moving parts, which over time ware out, and add say .0005” variations in several stages of the bullet forming process and tolerance stacking will occur.

 

[EvilRoy]

Do you have the expander mandrel stem out of the sizing die?

Yes

 

[EvilRoy]

I use the Redding neck bushing resizing dies in both full length and neck for six different cartridges, and what I found is to screw down bushing retainer screw until it stops on the neck bushing, then back the screw off by 1/16 of a turn to allow the bushing to float, which allows the bushing to self centered on the case neck. I also lube the top of the bushing rim and bottom of the bushing retainer screw with graphite powder. Cartridge case neck runout is usually no more then .0003”-.0006” without or with a bullet seated.

Also. The choice of Hornady bullets is always suspect in that their bullet along with Speer, Sierra, and Nosler bullets are not true match bullets. At least in my opinion. There are many small variations that occurs during the manufacturing process. Sierra at times holds a higher production standard for their match grade bullets, but can vary from one production lot to next production lot. The thing to consider is the bullets are made on production machines with moving parts, which over time ware out, and add say .0005” variations in several stages of the bullet forming process and tolerance stacking will occur.

I am thinking about getting some Berger bullets since they are supposed to be as good as any for match. I have concidered maybe bullets are total crap for seating. I don't have this issue with the 308. So something is different.

 

[boltfluter]

One thing comes to mind. Check the concentricity of the bushing you are using. I have seen more than one bored off center. Just a thought. Good luck.

Paul

 

[rwj]

One thing comes to mind. Check the concentricity of the bushing you are using. I have seen more than one bored off center. Just a thought. Good luck.

Paul

The same issue could also exist in the die body bore where the bushing is placed…

 

[EvilRoy]

One thing comes to mind. Check the concentricity of the bushing you are using. I have seen more than one bored off center. Just a thought. Good luck.

Paul

I will. That is is a good idea to check it.

 

[JimSC]

is the Grendel a AR and the .308 a bolt gun? Although not as extreme as your problem, my Grendel AR also has a concentricity problem that I never see in my bolt rifles

 

[EvilRoy]

is the Grendel a AR and the .308 a bolt gun? Although not as extreme as your problem, my Grendel AR also has a concentricity problem that I never see in my bolt rifles

The Grendel is an AR. My 308 is a M1A national match. However the ammo itself is Hornady and so I tried new unfired Lapua brass. It happens to the Lapua brass also. Crazy high runout is going on with the Grendel reloading. My 308 stuff not really any issues that I would get upset about.

 

[HandgunHTR]

So do you have a match chamber in the Grendel AR? If not, it probably won’t matter that much, especially if you are loading from the magazine. The main question is have you shot those loads to see how they perform?
You may be obsessing over a detail that isn’t important for the platform you are shooting.

 

[Sniper338]

You said you have a consentrisity guage. Have you ran bullets on it?

 

[JimSC]

The Grendel is an AR. My 308 is a M1A national match. However the ammo itself is Hornady and so I tried new unfired Lapua brass. It happens to the Lapua brass also. Crazy high runout is going on with the Grendel reloading. My 308 stuff not really any issues that I would get upset about.

Necks are probably getting tweaked during ejection. My Grendel has a Wilson Combat barrel bedded in a Precision FIrearms receiver and BCG. The concentricity issue drove me up a wall for a while also, expecting bolt gun readings and groups from my AR. Then I just accepted it and realized the new AR-T prone targets have twice the size X and 10 rings than F class targets for a reason.

 

[Sniper338]

Necks are probably getting tweaked during ejection. My Grendel has a Wilson Combat barrel bedded in a Precision FIrearms receiver and BCG. The concentricity issue drove me up a wall for a while also, expecting bolt gun readings and groups from my AR. Then I just accepted it and realized the new AR-T prone targets have twice the size X and 10 rings than F class targets for a reason.

Brass usually dents case necks in, it doesnt screw up consentricity.