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Would like some opinions on a 12" grendel shooting 115 to 123 gr hunting bullets.
What powders work well for those that produce good accuracy and velocity, and are temp stable?
I figure some of have traveled this road already and hope to Rast track from your experience.
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Ar-comp,xbr8208,h322,varget,h4895.
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What he said ^^^
Ill add Benchmark if you can find it. Tac works well also
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My first choice would be N135. You will get complete powder burn at 12" with really low SD's. I used this with Sierra 107's and the SD's were below 5. That was measured over 20 shots and 6 different charge weights.
I'd try H322 or Xterminator as well. Again, you should get close to or complete powder burn at 12".
If loading close to max charge weights, I wouldn't worry about temp stability unless hunting when it's in the 80's or 90's.
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What kind of velocity should I be realistically expecting? May make a difference on bullet selection.
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Shooter31 Wrote:What kind of velocity should I be realistically expecting? May make a difference on bullet selection.
With the bullet weights you listed. 2300 fps are less at max safe charges, depending on bullet type, powder,primer and case fill due too ojive contact to lands.
If your barrels throat allows a long coal length... say in the 2.280 to 2.290 coal length range with your choice of bullet. And with say ar-comp and a cci450 primer from a hornady or starline case.
You can expect too hit max pressure around the 2300 to 2350 fps range.
I have killed plenty of hogs,deer and yotes with a 120 gold dot leaving the barrel at 2315 fps and keeping my shots inside 150 yards with my 12 and 12.5 inch grendels.
But I much prefer a all copper bullet in the 85 to 100 grain flyweight range for my shot guns.
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muvef Wrote:My first choice would be N135. You will get complete powder burn at 12" with really low SD's. I used this with Sierra 107's and the SD's were below 5. That was measured over 20 shots and 6 different charge weights.
I'd try H322 or Xterminator as well. Again, you should get close to or complete powder burn at 12".
If loading close to max charge weights, I wouldn't worry about temp stability unless hunting when it's in the 80's or 90's.
All modern powders are completely burnt before the barrel reaches the gas port. Even on carbine length gas systems.
If it wasnt the gas block and gas tube would clog up very quickly with sunburnt powder.
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OK, then next question would be. Should I jump down in weight. Say the 100 gr ballistic tip or 100gr TTSX? Most likely any hunting shot would be under 200 yards but theirs a chance to do 300-350 yards and hate to pass on something nice cause of velocity loss at that range not being enough for expansion. I really wish someone would come out with a good hunting bullet in the 110gr area for med velocities. Guess were not a big enough market.
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07-31-2022, 07:05 PM
(This post was last modified: 07-31-2022, 07:11 PM by VASCAR2.)
I wouldnt use the 100 grain TTSX in a short 6.5 Grendel barrel for hunting. This bullet needs close to 2000 FPS to expand. The 100 grain Nosler Partition would work as well as the 100 grain Nosler Ballistic Tip hunting. The Nosler 129 grain Accu Bond Long Range expands down to 1300 FPS and has a good BC.
https://www.nosler.com/6-5mm-129gr-accub...100ct.html
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myrifle Wrote:All modern powders are completely burnt before the barrel reaches the gas port. Even on carbine length gas systems.
If it wasnt the gas block and gas tube would clog up very quickly with sunburnt powder.
Huge fireballs out the end of a barrel IS unburnt powder burning... Just an FYI.
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muvef Wrote:Huge fireballs out the end of a barrel IS unburnt powder burning... Just an FYI.
+1
Exactly!
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07-31-2022, 09:05 PM
(This post was last modified: 07-31-2022, 09:08 PM by Harpoon1.)
VASCAR2 Wrote:I wouldnt use the 100 grain TTSX in a short 6.5 Grendel barrel for hunting. This bullet needs close to 2000 FPS to expand. The 100 grain Nosler Partition would work as well as the 100 grain Nosler Ballistic Tip hunting. The Nosler 129 grain Accu Bond Long Range expands down to 1300 FPS and has a good BC.
https://www.nosler.com/6-5mm-129gr-accub...100ct.html
+1
Another sensible, well reasoned reply!
100 grn Partions, and/or, 90 TNT (on hogs/varmints) are going to be tough to beat out of a SBR! IMO
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07-31-2022, 09:12 PM
(This post was last modified: 07-31-2022, 09:25 PM by Harpoon1.)
Shooter31 Wrote:OK, then next question would be. Should I jump down in weight. Say the 100 gr ballistic tip or 100gr TTSX? Most likely any hunting shot would be under 200 yards but theirs a chance to do 300-350 yards and hate to pass on something nice cause of velocity loss at that range not being enough for expansion. I really wish someone would come out with a good hunting bullet in the 110gr area for med velocities. Guess were not a big enough market.
Use the 100 grain Partitions. Or maybe even the 120 Gold Dots! Monolithic Copper bullets out of a Grendel SBR/Pistol are a crap shoot, at best! You typically just cant get enough velocity to guarantee their advertised performance, unless youre talking about typical Bowhunting ranges or at point blank! The lead nose Partitons are a solid performer. At almost any reasonable impact speed! The Gold Standard, what all other bullet performance is measured by! If aint broke
..YMMV.
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muvef Wrote:Huge fireballs out the end of a barrel IS unburnt powder burning... Just an FYI.
No. No it's not at all.
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Harpoon1 Wrote:Use the 100 grain Partitions. Or maybe even the 120 Gold Dots! Monolithic Copper bullets out of a SBR Grendel are a crap shoot! You typically just cant get enough velocity to guarantee their advertised performance, unless youre talking at point blank range! The lead nose Partitons are a solid performer. The Gold Standard. If aint broke
..YMMV. 
That's not even remotely correct on the all copper rounds.
I can name 2 that will expand nicely from the speeds that a short barrel can make.
1. Cavity back 105 mkz
2. Maker trex either 85, 95 or 110 grain.
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07-31-2022, 09:28 PM
(This post was last modified: 07-31-2022, 09:31 PM by Harpoon1.)
myrifle Wrote:No. No it's not at all.
Can you provide any fact based evidence or data to support your assertions?
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07-31-2022, 09:29 PM
(This post was last modified: 07-31-2022, 09:52 PM by Harpoon1.)
myrifle Wrote:That's not even remotely correct on the all copper rounds.
I can name 2 that will expand nicely from the speeds that a short barrel can make.
1. Cavity back 105 mkz
2. Maker trex either 85, 95 or 110 grain.
Well, fair enough, I havent used either one of those bullets!
Point taken!
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Speaking of accubond, I have some 130gr sierra tipped game kings. I just don't know what the minimum velocity is for those to expand.
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Harpoon1 Wrote:Can you provide any fact based evidence or data to support your assertions?
Have you ever seen or heard of a clogged up gas port, gas block or gas tube from unhurt gun powder?
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07-31-2022, 11:40 PM
(This post was last modified: 08-01-2022, 12:15 AM by Klem.)
Shooter,
A 12" (slow) barrel with a small case like Grendel (also slow) represents a handicap requiring offset by careful choice of powder and bullets. Do this by choosing the lightest bullets and fastest powders. Something that will burn as much as possible before the bullet exits. The compromise between velocity and powder burn will see about 5-10% unburnt exiting the barrel, but there's nothing you can do about that without lowering the velocity even further.
I assume 'temp stable' means least variation of velocities between night and day, winter and summer - so single-based powders. The main manufacturer of mostly available single-based is ADI, sold in the US by Hodgdens (from slowest to fastest: H322, Benchmark, 8208, H4895).
I recommend powders like H322, Benchmark, and 8208, using bullets no heavier than 100gn.
,
Velocities will be about 2,300+ fps for 100gn or lower, and 2,180- fps for 120+gn bullets.
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