AR15 reloads

[Speed3]

I suggest starting at 23.5gr and working up. I use 23.5gr with 77gr sierras.

I use 23.8gr of varget with 77's. Working up a 75gr load soon

 

[deesly1]

HUH?

How does the revolution become inconsistent?

You have to compare apples to apples. Work up a load with 53 gr SMKs and compare to 77 gr SMKs at a reasonable range (100 - 300 yards).

55 gr are NOT match bullets.

Revolution can become inconsistent by taking a lighter projectile and spinning to faster then its heaver counterpart. The original poster said he was using a 1:7 twist barrel shooting 55gr bullets. I suggested a heavier grain to stabilize the bullet better in flight at 200 yards.

maybe this video can say it better than me:

https://www.youtube.com/watch?v=ndeET4A67Dk

 

[Melnic]

The 1:7 twist is what I ran the original chrono on. I did not have the 1:9 twist barrel in yet.
The 1:7 twist will not have optics put on it, its all iron sights so I'm not going to do too much with it.
I'm working up loads for my 1:9 twist now. It is no match barrel, its an inexpensive Del-Ton HBAR which I'm not sure how accurate I can even get it.

200 yards will be rare for me, but heck, if its still accurate at 100 yards, I'm good with 69g SMK bullets for it. I keep being told by range fellows to use the 69SMK, I already have a mess of them.

 

[Pinecone]

Also doesn't the army use 62's because of terminal performance gains?

Yes, in a way. 62 gr SS109 bullet was designed to penetrate a helmet at some 500 or 800 meters.

NOT because they are more accurate. They aren't.

 

[Pinecone]

Revolution can become inconsistent by taking a lighter projectile and spinning to faster then its heaver counterpart. The original poster said he was using a 1:7 twist barrel shooting 55gr bullets. I suggested a heavier grain to stabilize the bullet better in flight at 200 yards.

maybe this video can say it better than me:

https://www.youtube.com/watch?v=ndeET4A67Dk

HOW IS IT INCONSISTENT?

It spins at a rate based on the muzzle velocity and the twist rate. A light, higher velocity bullet in a fast twist guns rotates the bullet faster. The faster rotation means more stability.

That video does NOT explain what you say it does. All he says is that if you have the "wrong" twist rate, it MAY not be as accurate. NO reasoning why. He doesn't explain squat.

 

[Russ D]

Revolution can become inconsistent by taking a lighter projectile and spinning to faster then its heaver counterpart. The original poster said he was using a 1:7 twist barrel shooting 55gr bullets. I suggested a heavier grain to stabilize the bullet better in flight at 200 yards.

maybe this video can say it better than me:

https://www.youtube.com/watch?v=ndeET4A67Dk

I don't dispute the science behind it, but in real world testing I've yet to find a single person who cannot get 55 grain match grade ammo to shoot lights out in a 1/7 twist AR out to 200 yards. I accuracy test a lot of .223 reloads and I started with 75's and 77's so I have a good bit of experience with those as well.

 

[Speed3]

I don't dispute the science behind it, but in real world testing I've yet to find a single person who cannot get 55 grain match grade ammo to shoot lights out in a 1/7 twist AR out to 200 yards. I accuracy test a lot of .223 reloads and I started with 75's and 77's so I have a good bit of experience with those as well.

What 55gr bullet do you shoot, I would like to load some up since they are cheaper.

 

[Pinecone]

What 55gr bullet do you shoot, I would like to load some up since they are cheaper.

Notice he said MATCH GRADE bullet.

These are not the cheap ones.

 

[Pinecone]

I don't dispute the science behind it, but in real world testing I've yet to find a single person who cannot get 55 grain match grade ammo to shoot lights out in a 1/7 twist AR out to 200 yards. I accuracy test a lot of .223 reloads and I started with 75's and 77's so I have a good bit of experience with those as well.

There is no science behind it. There is a lot of internet expertise that too fast a twist makes the bullet inaccurate.

The only problem with a very fast twist is, that with light bullets, mainly of thin jacketed varmint types, you can spin the bullet fast enough to have it disintegrate in flight. But until you do this, accuracy will be fine.

 

[Speed3]

Notice he said MATCH GRADE bullet.

These are not the cheap ones.

Without knowing for sure I can't say, but I bet they are cheaper than a 77 SMK.

 

[paxfish]

Sierra Blitz King 55 grainers are a little bit cheaper but not much. They are a premium, highly accurate bullet for sure. They have the added benefit of being an excellent small game bullet.

 

[paxfish]

I suggest starting at 23.5gr and working up. I use 23.5gr with 77gr sierras.

That sounds reasonable. I settled at 24.0 Varget under 77 SMK in our 20" service rifle. It has a fairly tight Satern barrel, and showed some pressure signs above that.

It doesn't much like 69's, but LOVES 77's. Here is 100 yards for a .65 average across 3 groups of 5 shots. And then some 69's below it.

 

[Melnic]

I have been looking at my loads at 50 yards because I was also shooting something else while giving the barrel time to cool.
I think I need to shoot at 100 yards or I may be wasting my time.

 

[paxfish]

maybe not. But definitely do 5 shot groups at a minimum and baseline using that. In my mind, the 4th and 5th shot are key to providing reliable, actionable data.

Using the free OnTarget app for later analysis is key also....

 

[Russ D]

That sounds reasonable. I settled at 24.0 Varget under 77 SMK in our 20" service rifle. It has a fairly tight Satern barrel, and showed some pressure signs above that.

It doesn't much like 69's, but LOVES 77's. Here is 100 yards for a .65 average across 3 groups of 5 shots. And then some 69's below it.

Unless you are committed to Varget, I'd try a different powder and see if the results change. That is if you are interested in getting small groups with the 69's.

 

[dist1646]

That sounds reasonable. I settled at 24.0 Varget under 77 SMK in our 20" service rifle. It has a fairly tight Satern barrel, and showed some pressure signs above that.

It doesn't much like 69's, but LOVES 77's. Here is 100 yards for a .65 average across 3 groups of 5 shots. And then some 69's below it.

I found that some barrels just prefer 77's over 69's. Even so, I have managed to shoot 200-15X on the mr52 target more than once with them. Prone with sling, iron sights. I was using N140.

 

[Pinecone]

Without knowing for sure I can't say, but I bet they are cheaper than a 77 SMK.

53 gr Match King - $18.77 per 100 (Powder Valley)

69 gr Match King - $20.69 per 100

77gr Match King - $27.38 per 100

Slightly cheaper, but not a huge amount.

 

[paxfish]

Unless you are committed to Varget, I'd try a different powder and see if the results change. That is if you are interested in getting small groups with the 69's.

Yeah - No need for the 69's. I don;t think the ARcomp groups were much better for 69s though.

Now, 55's in the carbine - YEAH!

 

[Russ D]

53 gr Match King - $18.77 per 100 (Powder Valley)

69 gr Match King - $20.69 per 100

77gr Match King - $27.38 per 100

Slightly cheaper, but not a huge amount.

I like 55 Vmax's or even the 50's. They are close to match quality, and you can find some really good deals.

 

[Sticky]

I like 55 Vmax's or even the 50's. They are close to match quality, and you can find some really good deals.

Agreed.. the polymer tipped projectiles are very consistent. I use 55gr Vmax and also Nosler BT's.. both are match grade as far as I am concerned, shoot as well as SMK's all day long at moderate ranges.