Clone the Clone: IMI 77gr Razor Core

[FredHammer]

IMI 77gr SMK Razor Core is some great shooting factory ammo. I haven't loaded 5.56 in 15yrs but saved my IMI brass. Gave it a go with the following best performing powders: (Velocities and group sizes practically identical to IMI 77SMK Razor Core)

WOA 18" SPR
2-10X36 Trijicon Credo in ARC rings

Bullet: 77SMK
Powder TAC @24.2gr
Case: IMI 1X
Primer: CCI 41
COAL: 2.255
MV: 2712fps SD: 16fps (IMI was 2711fps SD:15fps)
Temp: 66F.
Ele: 750ft
Group: .53MOA 10 shot
Neck Tens: .0035

Bullet: 77SMK
Powder: N135 @23.7gr
Case: IMI 1X
Primer: CCI 41
COAL: 2.255
MV: 2716fps SD: 7
Temp: 66F.
Ele: 750ft
Group: .54 MOA 10 shot
Neck Tens: .0035

Notes:
N135 was nice surprise. I haven't read much on the powder for 77SMK. 23.7gr gave a bit of ejector shine, but so does IMI.
IMI ammo was COAL: 2.245. I need to load these two loads at that 2.245 COAL and see what happens.
The neck tension on my loads seemed/felt tight. I will get a .0015 larger mandrel and test again.
Trijicon Credo. Man, what a neat little scope. That thing banging out these groups makes me happy.
I learned I can swage/cut the primer crimp from the primer pockets with a VLD chamfer tool. So damn handy!

 

[FredHammer]

N135 showing the best ES/SD so far.

 

[BuildingConceptsllc]

N135 showing the best ES/SD so far.
View attachment 8260836

So that's 20 consecutive shots with an SD of 6.7 ?

 

[FredHammer]

So that's 20 consecutive shots with an SD of 6.7 ?

Yes, and N135 in a 708 with 120gr Hammer hunters went 40 shots for 9 SD. Two 20 shot strings. 39.5gr N135 under 200.20X 308 shoots fantastic also. Need to ES/SD test it. Very impressed with N135 so far.

 

[BuildingConceptsllc]

Yes, and N135 in a 708 with 120gr Hammer hunters went 40 shots for 9 SD. Two 20 shot strings. 39.5gr N135 under 200.20X 308 shoots fantastic also. Need to ES/SD test it. Very impressed with N135 so far.

Yeah that's really good for a 223 round. What's the temp stability like with that stuff?

 

[FredHammer]

Yeah that's really good for a 223 round. What's the temp stability like with that stuff?

and for fucking gas guns? It unreal.
When I loaded N135 for the 200.20X 308 @25F. it got better velocity than the usual powder players, Varget, N140, 4064, IMR 4895, etc, It also produced the best precision. When I shot at 60F., the regular players were getting back online with the precision more comparable. I haven't shot in warmer weather with the N135 308 yet.

The 708AR fired from 70F to 90F. with N135 only increased velocity 15fps. That is fantastic compared to other powders, even extreme line of powders by Hodgdon.

Edited to add: Well, I could just look at my own damned data for temp sensitivity of N135 in 5.56.
I shot the same load on two different temp days with that data presented right in this thread. (FX True Ballistics Chrono)

66F. - 2716fps
40F. - 2703fps

26F difference in temp, 13fps in velocity. What's that give, .5fps per degree sensitivity between those two temps? With the powder matching the ambient temp that is great! Seems to stay true to that .5fps in the 708AR mentioned. 15fps increase in the hotter temps, but still 20fps spread between 70-90F. I'm digging it!

 

[BuildingConceptsllc]

and for fucking gas guns? It unreal.
When I loaded N135 for the 200.20X 308 @25F. it got better velocity than the usual powder players, Varget, N140, 4064, IMR 4895, etc, It also produced the best precision. When I shot at 60F. The regular players were getting back online with the precision more comparable. I haven't shot in warmer weather with the N135 308 yet.

The 708AR fired from 70F to 90F. with N135 only increased velocity 15fps. That is fantastic compared to other powders, even extreme line of powders by Hodgdon.

I might have to get me a jug of that and check it out myself. I think this is what @Molon runs in his AR's as well IIRC.

 

[FredHammer]

Here is the 77 IMI Razor Core: 18" BA SPR fluted barrel: Smaller shot sample, but already tailing behind in ES/SD

Out of 16" Faxon:

 

[FredHammer]

77gr Berger TACT 2.255”
N135 23.7gr
IMI brass
CCI 41
WOA 18” SPR

 

[FredHammer]

Ginex proved a little spicey compared to CCI #41. Gonna drop to 23.5gr & 23.6 to see if ES/SD improves:

 

[FredHammer]

More Ginex primer testing. It’s like a smooth climb down the ladder per 1/10th grain N135 reduction:

Berger TACT 77gr
23.6gr N135

23.5gr N135

(IMI 77 SMK Razor core shot 2731fps 16SD)

Ejector shine on the case heads with the 23.5gr. No shine on IMI razor core. This 23.5gr charge weight is about identical in MV with razor core, with less ES/SD but seems to be pressuring quicker to get that velocity. If I didn’t care about the brass, fire & forget, I’d stay here. I will drop to 23.3 to see if that smear goes away.

 

[FredHammer]

I intend to clean this thread up and provide the conclusions, but two trends I'm finding

1. It seems N135 pressures more with Ginex primers, but TAC stays the same with both primers. Don't know why, other than the chemical composition differences between the two powders, with one extruded and the other ball.
2. First precision testing shows the 24.2gr TAC both primers is producing tighter groups than the single digit SD 23.6gr N135. Just my luck this would happen. LOL. TAC - it's like the trailer park hot chick that's rough around the edges, but bangs like a champ.

 

[BuildingConceptsllc]

I intend to clean this thread up and provide the conclusions, but two trends I'm finding

1. It seems N135 pressures more with Ginex primers, but TAC stays the same with both primers. Don't know why, other than the chemical composition differences between the two powders, with one extruded and the other ball.
2. First precision testing shows the 24.2gr TAC both primers is producing tighter groups than the single digit SD 23.6gr N135. Just my luck this would happen. LOL. TAC - it's like the trailer park hot chick that's rough around the edges, but bangs like a champ.

Yeah that's why I settled on it. I played with other stuff for a while though never N135, but I always came back to Tac because it meters so well and the groups I got were just fire. For the 223 round, the SD isn't as big of a concern to me as say my 6m, just because I know I'm not shooting as far as 6cm or 6.5cm so a slightly higher SD wasn't as concerning as what I got on paper and at a decent distance on paper (out to 500 yds). I couldn't duplicate the groups I got with Tac and the SD still wasn't anything that upset me. Being able to load with Tac in a progressive and meter well is another reason it's popular and attractive to me so. That said, your numbers with N135 really do look great and I've not tried it so I could change my mind there.

How big are the kernels in that N135?

 

[FredHammer]

Yeah that's why I settled on it. I played with other stuff for a while though never N135, but I always came back to Tac because it meters so well and the groups I got were just fire. For the 223 round, the SD isn't as big of a concern to me as say my 6m, just because I know I'm not shooting as far as 6cm or 6.5cm so a slightly higher SD wasn't as concerning as what I got on paper and at a decent distance on paper (out to 500 yds). I couldn't duplicate the groups I got with Tac and the SD still wasn't anything that upset me. Being able to load with Tac in a progressive and meter well is another reason it's popular and attractive to me so. That said, your numbers with N135 really do look great and I've not tried it so I could change my mind there.

How big are the kernels in that N135?

So, the N135 doesn't group bad, I really am picking nits between the two powders, but the TAC loads are what I call "forgiving." They still print great even when I think I threw the shots. With the N135 if I think I threw the shots, welp there they were, flew out the group!

N135 is small kernel and meters like a dream. Chargemaster dispenses with rare overage, unlike other extruded powders. Fills the case nicely too. I think the great SD is two part: 1. The kernels weigh more precise, unlike TAC where I can add or subtract a little and don't see the scale move. 2. The case fill is kept in check as it's right at the bullet base. No back & forth powder column in the case from movement.

After this coffee gonna grab some cold weather chrono reads this morning.

 

[BuildingConceptsllc]

So, the N135 doesn't group bad, I really am picking nits between the two powders, but the TAC loads are what I call "forgiving." They still print great even when I think I threw the shots. With the N135 if I think I threw the shots, welp there they were, flew out the group!

N135 is small kernel and meters like a dream. Chargemaster dispenses with rare overage, unlike other extruded powders. Fills the case nicely too. I think the great SD is two part: 1. The kernels weigh more precise, unlike TAC where I can add or subtract a little and don't see the scale move. 2. The case fill is kept in check as it's right at the bullet base. No back & forth powder column in the case from movement.

After this coffee gonna grab some cold weather chrono reads this morning.

I think case fill and just being extruded vs ball is why. Tac should be more precise in terms of weight, but it may be that your scale just can't detect a movement until it's large enough to register with the larger v135 kernel.

I do know that my loads with Tac are always full and maybe a little compressed in lapua brass but the extruded are usually better sd than ball in my experience.

 

[ZA206]

I intend to clean this thread up and provide the conclusions, but two trends I'm finding

1. It seems N135 pressures more with Ginex primers, but TAC stays the same with both primers. Don't know why, other than the chemical composition differences between the two powders, with one extruded and the other ball.
2. First precision testing shows the 24.2gr TAC both primers is producing tighter groups than the single digit SD 23.6gr N135. Just my luck this would happen. LOL. TAC - it's like the trailer park hot chick that's rough around the edges, but bangs like a champ.

TAC = Great velocity, but with sketchiness and sometimes a magically accurate load. One of my all time best loads is a 55 ZMax/VMax and 25 gr of TAC at 2.240” COL (single hole groups). I’ve also had TAC give me like +5” groups with match bullets in combos it hated… I was like WTF? Stick powders seem to give me good, better & best style results with match bullets, but TAC is kinda bipolar. LOL… like a hot trailer park chick.

I can’t quit TAC, I love it.