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RetNav6.5

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Reply with quote  #1 
Craig asked me to share the results I have gotten so far with my load development.

I will start with what equipment I am using and a brief summary of the process. I use a Hormady LNL AP press, I also reload for 223, 9mm and 380 Auto. During resizing I bump the shoulder back .004. My rifle will manually extractor the cases at .003 but I got one thousandth more for insurance. I am using Hornady sizing die and trim to 1.515 using a WFT trimmer. I weigh each charge using a RCBS beam scale. I use a Forster BR seating die to seat the projectiles.

I don't have a fancy range to shoot at. It is a BLM built public range, with berms at 100, 200 and 300 yards to shoot from and is first come first served. In past years it was rare to find anyone out there. This year it is common to have to wait your turn to get to shoot.

I shoot over a Caldwell chronograph and record the results with the iPad app. Here is what I have done so far. I worked up using .3 grain increments from 27.2. My shooting showed an accuracy node in the 27.5-27.8 range. On my next trip out I went with 5 rounds each in .1 grain increments 27.5-27.9. The Temp that day was 65F and barometric pressure of 25.36 inhg. Elevation at the range is 5410 feet.

The 27.6 load looked to be the most promising so I have focused on there and am trying different COAL settings to see where I can find the best is for my rifle. I am using IMR 8208 xbr, Sierra 120 SMK and Winchester SR primers with Hornady brass. Here is what I have so far.

COAL:      MV:      SD:    ES:     MOA:
2.265      2590     2.3       6      .648
2.260      2595    14.8     33      .717
2.255      2602      6.7     17      .552
The take away I am seeing here is that the closer the bullet is to the lands does not always result in the best group. I plan on shooting 2.265 again since I only shot 1 five round group at that setting and shot multiple groups at the other two settings. I am also going to try 2.250 & 2.245 to see what happens at those settings. I am not in to loading hot so I do not plan on looking for the next higher node but will continue to experiment at this node.


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Borrego Bob

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Reply with quote  #2 
Excellent thanks yes that take away is correct i was wrong on early posts about the grendel ii. 
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nobody

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Reply with quote  #3 
the thing we need to remember is the 6.5 Grendel is not a match winning round. even in a bolt gun it is not going to win matches. shooting sub M.O.A. groups is great for any rifle. even better out of a semi auto rifle. I am a match shooter. if I have a sub M.O.A. semi auto rifle with hand loads i'm happy. we have to remember bolt guns are the best of the best. even a factory bolt gun with a kinda good barrel will out shoot a semi auto.
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WFA

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Reply with quote  #4 
I have found that shorter COAL work best in a number of my MSR uppers in multiple calibers. In some cases I thought that the bullet maker's reloading manual(s) were simply staying at magazine length, or interested in reliable feeding only... until I was having accuracy issues and tried "following directions". The published COAL produced the best accuracy in most (but not all) cases. I'm not saying this is a "rule", but rather something to consider.

WFA

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RetNav6.5

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Reply with quote  #5 
I shot some additional rounds with COAL at 2.245 & 2.250 yesterday. Neither of these shot better than the 2.255 and the MV was a little lower, I was expecting to see a little higher MV. The temp was 74F yesterday. IMR 8208xbr is not supposed to be that temp sensitive and going by the MV difference I would concur with that.
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RetNav6.5

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Reply with quote  #6 
They opened the range back up on monday after being closed down for a couple week due to a 4,000 acre wildfire sparked by someone shooting green-tips. Turns out you are not allowed to shoot them between May-October in this part of Idaho. I was not aware of this and is nice to know.

I am probably boring some of you out there, but since I am a novice reloader this is all new ground for me and hoping other may benefit from what I seeing. If anyone has any pointers that would be helpful I am all ears. I am not a match shooter and only compete with myself.

Previously with my handloads for my other rifles I would stumble upon a load that shot nice and leave it at that. With my Grendel loads I had decided to experiment with different settings and find out what this would produce, all settings are to be using safe reloading practices. Someone over on the Facebook Group suggested I try going a little shorter, down to 2.220 and see what I got. I loaded up 5 rounds each at 2.235, 2.230, 2.225 and 2.220. Yesterday I was able to get out to the range and shoot them. I like what I see with the 2.220 & 2.225 settings and will investigate further.
 
COAL:      MV:      SD:    ES:     MOA:
2.235      2634     30.4    76     .900
2.230      2588     12.8    34     .838
2.225      2600     22.7    56     .402
2.220      2582      8.9     22     .590

For those that like to see pictures here is what the groups looked like. The measurement include my flyers. My trigger and I were working really good together yesterday. The flyer for the group shot at 2.220 was caused by horse fly biting my back on the 5th shot. I was surprised the group held together as well as it did. As soon as I get done shooting up the Midway targets I have printed up I will start using the Grendel Challenge targets.

6.5Grendel_2Aug17.jpg 

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nobody

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Reply with quote  #7 
i'm interested. what powder, primer and bullets used in your testing?
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RetNav6.5

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Reply with quote  #8 
I am testing Sierra 120 gr SMK's over IMR 8208 xbr and use Winchester SR primers. Barrel is Satern 24", Grendel II chamber and 1:8 twist.
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nobody

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Reply with quote  #9 
 did you chrony these rounds? it sounds like you have clued in on your barrels tune.
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Borrego Bob

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Reply with quote  #10 
What powder load was this?
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RetNav6.5

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Reply with quote  #11 
Nobody,

Yes I did. Still trying to make sense of some of the data. All part of the learning curve.
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RetNav6.5

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Reply with quote  #12 
Craig,

I am still working with 27.6 gr of 8208. Playing with COAL to see where I might find the most accurate load.
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