New 7mm-08 Canyon Buster

I'm not sure what you mean by the statement. I saw slow motion videos of scope and barrels touching when there was only a dollar bill thickness between them. So, I make sure to have 1/16" and put the front ring as far forward as possible.
Sorry, I was referring the question to someone commenting on how there must only be a sliver of space between scope and barrel. My question was to them why would you want it any different? Especially based on that stock profile, and really in any other "normal" set up for hunting where no iron sights are on the gun.
 

That GIF was hilarious! I expected so much out of you!

Here goes:

So, I discovered my Kimber 84 has a short throat. I need a COAL of 2.700" with the 120 HH. Once I diagnosed that issue:

Bullet: 120 HH
Powder: Varget 44gr
Primer: WLR
Case: Lapua
MV @ 25 F. 750 ft ELE, 3072fps SD: 8fps
Accuracy: MOA, (touching)

I am going to get the Lee factory crimp die. I hear that might shrink up the groups. I mean, what does Butterbean know anyway 😄
D0A5AE4D-B335-44EE-8589-494FE3E469BF.jpeg


Gave the scope a few clicks right. :cool:
 
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That GIF was hilarious! I expected so much out of you!

Here goes:

So, I discovered my Kimber 84 has a short throat. I need a COAL of 2.700" with the 120 HH. Once I diagnosed that issue:

Bullet: 120 HH
Powder: Varget 44gr
Primer: WLR
Case: Lapua
MV @ 25 F. 750 ft ELE, 3072fps SD: 8fps
Accuracy: MOA, (touching)

I am going to get the Lee factory crimp die. I hear that might shrink up the groups. I mean, what does Butterbean know anyway 😄
View attachment 318200

Gave the scope a few clicks right. :cool:
Thanks for sharing, looks sweet. I just got a box of 120 Hammer Hunters and hope my light weight 7mm-08 can produce something similar!
 
Okley Silly Doakley! You fellers are lucky, because I like ya'll. I went out in the cold and toiled to get this latest data. Load developing a new bullet for a new gun with various powders is just such a rough task! 😄

I ran the 7mm-08 through the powder cupboard to "Fool around and find out!" Ok, so lets get to the report: Some of the info is repetitive for copy and paste purposes to post on another forum.

Background/Research

New Kimber 84M Hunter 7mm-08 purchased for the dispatching of coyotes, hogs, deer, black bear, etc. Also dual role of truck gun and lightweight long-range spot & stalk canyon, or mountain busting. Barrel was thoroughly cleaned with foaming bore cleaner to remove the factory shot copper. I won't clean the barrel further until accuracy falls off. (GAP, Kreiger advice) Rifle was purchased because of the stainless action/barrel and aluminum pillar bedded polymer stock. I do not fret a scratch on a polymer stock, but I will cry tears of woe should it happen to a beautiful wood stock.

Kimber guarantees a maximum 1 MOA 3 shot group. 3 shot group because it sports a pencil sporter barrel. This barrel will throw shots beyond the 3rd to unacceptable MOA groupings. So, I know the platform in which I am dealing. I rarely need more than 3 shots on whatever I am hunting, so if the first two shots are spot on, then that is acceptable. (Calm clean Kills) My research findings that support Kimber's guarantee were gathered from Youtube video reviews of this very rifle. This understanding soothed my 5-10 shot sub-MOA group requiring brain, as I am used to my precision rifle performance. Again, this is a 1-2 shot truck, lightweight canyon brambling gun.

The LRH forums exposed me to the existence of Hammer Bullets. I am a grass roots kinda guy and certainly like to explore the mysteries of a cult following. I was influenced by Zen Archery and Butterbean to try this company's bullet offerings. So, why not just start from scratch with a new gun and new bullet? Butterbean seemed to be the most authority on how to load Hammer Bullets. I watched and listened to his videos and had a phone chat about the matter. I came away from the conversation with the notion I needed to increase neck tension and crimp the hammer bullets for the best results. Butterbean also advised to start with a full case of Varget, and should I not like the results, to try IMR8208 XBR. I don't own that particular powder, but I do own a plentiful amount of the powder in which IMR8208 XBR was derived, IMR3031. Zen Archery recently posted he thought ball powders of a similar burn rate as extruded yeild more velocity. I also found this to be true and included AA2520.

My Kimber 84M Hunter has a short throat for the 120gr Hammer bullets. I tested DST and jam utilizing the sharpie marker on the bullet until the bullet length showed no signs of contacting the lands. This resulted in a 2.700" bullet seating depth. I am just off the lands by .005" according to my tests. I estimate I am no more than .060" off the jam. I suspect there are two lands longer than the others in this rifle as indicated on the sharpie tests.

Execution/Results

I chose to start and find the maximum charge for the powders listed. I started at the maximum charges Hornady listed for their 120gr bullet. On the powders not listed by Hornady, I used my previous experience with 308 load development. I also referenced the burn chart of powders listed in the 11th edition of the Hornady handbook.

Powders tested with 120gr .284 dia Hammer Hunters:

Lapua brass
WLR primer
COAL: 2.700"
35 F. 750ft ele.

IMR 3031 - Extruded powder, not labeled as temp insensitive powder beyond the extruded nature

41.5gr produced 3115fps, 4 SD. Two shot group measured, .244". *** (Cloudy chrono 3084fps)
42gr Produced 3185fps, 8 SD. Two shot group measured, .319". Sticky bolt lift, flattened primers

AA2520- ball powder

44gr produced 3140fps, 7 SD. Two shot group measured, .147". No sticky bolt lift. Flattened primers *** (Cloudy chrono 3075fps)

45gr produced 3150fps, 24 SD. Two shot group measured, .190". Sticky bolt lift, flattened primers. Three shot group .403"

IMR 4895 - Extruded powder, not labeled as temp insensitive powder beyond the extruded nature

42.5gr produced 3000fps, 7SD. Two shot group measured, .190".

IMR Enduron 4166 - Extruded powder labeled as temperature insensitive

42.5gr produced 3058fps, 14 SD. Two shot group measured, .239". Sticky bolt lift, flattened primers

Varget - Extruded powder labeled as temp insensitive (Also confirmed in personal tests over 20yrs)

44gr produced 3072fps, 8 SD. Two shot group measured, .166". Three shot group .444"*** (Cloudy chrono 3075)

Moving Forward on the *** Marked Powders

There was an apparent pattern to the three shot groups vs the two shot groups. Each 3 shot group, except Varget, printed the 3rd shot high left of the two shots. It is very apparent. (Reference the photo)

I will end testing of the powders that produced sticky bolt lift. I will continue testing of:

Varget - 44gr with low SD, best three shot group, temperature insensitive. Summer temps/thinner air should have it flying 3100fps

IMR 3031 - 41.5gr gave good MV, excited to see what a 3 shot group will produce. Will try 41.7 to eek out some more velocity.

AA2520 - 44gr had great MV. Will need to test group accuracy. I am hesitant to pick this powder due to its temp sensitivity. (100fps variations in 308 testing from 20 F. to 80 F.) I'm excited to try 43 and 43.5gr. This powder is producing great MV and reducing charge is comforting.

The underdog will be the IMR 4895. It had less felt recoil than the other powders tested. 43gr might put the MV in comparison to the Varget.

4DF5806C-A387-4D62-B618-3A27845A8539.jpeg

4643A533-B698-4857-8AF9-31DF2D7B42E3.jpeg
 
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Dec 8th was a sunny chronograph condition day. I wanted to confirm velocities on an overcast/cloudy day on Dec 9th. (I've known sunny days to cause wonky readings.)

I also tried RL17:

120 HH
Powder: RL17 @ 48gr
Case: Lapua
Primer: WLR
MV: 3025fps
SD: 17
Group: 3 shots .330"
Pressure: No signs
Notes: Will try 48.5gr to achieve 3050fps and lower SD

44gr of Varget and AA2520 gave sticky bolt lift. 43gr AA2520 gave 3075fps with no pressure signs.

Next up:

43.5 Varget
48.5 RL-17
41.3 3031 (One case stiff bolt lift at 41.5)

I edited the Dec 9th cloudy day chrono readings above post
 
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