Hornady 6 ARC data for Lever too hot?

[chungus]

I am trying to work up a load for Berger 108gr Elite Hunters with Lever for my 6 ARC bolt gun. They list a max of 31.2 gr and 2850 FPS out of a 24" bbl. At 30.6 gr I am getting 2746 FPS out of a 16" barrel and ridged primers, extractor marks, and heavy bolt lift.

 

[Robert4]

Only losing 100-ish FPS with an 8" shorter barrel is telling you your load is over pressure. Differences in case, primer, powder lot, ambient conditions and barrels would easily cause this over pressure. Back off a little bit and try again.

 

[Mike Casselton]

I am trying to work up a load for Berger 108gr Elite Hunters with Lever for my 6 ARC bolt gun. They list a max of 31.2 gr and 2850 FPS out of a 24" bbl. At 30.6 gr I am getting 2746 FPS out of a 16" barrel and ridged primers, extractor marks, and heavy bolt lift.

Three separate high pressure signs.
I'm not sure why you would even need to ask this question.

Back off at least one full grain and creep your way up to maximum.

Maximum, meaning any one of your three signs and you are over pressure.


1. Cratered primers by themselves could be firing pin clearance or pressure issues. If the primers are beginning to flatten around their perimeter, that's one sign of high pressure.

2. An ejector mark by itself could be the rifle. Origin actions usually leave a skinny rectangle where the ejector cutout is. A Remington could have an ejector pin that is too long, or it might have a small burr around it's circumference.

3. Heavy bolt lift could be the type of action you have or even might just need some lube on the cocking cam and bolt lugs.


When you combine two of the above, it should be a big warning sign.
You have all three.
Pay attention to what your rifle is telling you.

 

[chungus]

Thanks for the replies. Yes I know there is no doubt I am over pressure and need to back off. I guess what I thought was strange was that I was seeing these signs below the listed maximum in the book. I don’t have a ton of reloading experience but with every other powder I have tried I have been able to creep up past the maximum before I saw any pressure signs so I found this unusual to be occurring at a decent amount below the listed max.

 

[Mike Casselton]

Maybe your brass is a bit small in your chamber. That could cause all of your issues.

 

[chungus]

Maybe your brass is a bit small in your chamber. That could cause all of your issues.

I guess anything is possible but with the same brass and other powders I am able to go above book max before I see pressure.

 

[stello1001]

Also, lever is very temp sensitive. It's fucking hot as balls right now. It's summer!!! You might be able to load this recipe and shoot it safely in the winter, for now though, decrease charge.

 

[Mike Casselton]

I guess anything is possible but with the same brass and other powders I am able to go above book max before I see pressure.

I made the assumption you were using new brass.

 

[olszta]

I thought I'd add the following for 6 ARC, AR15 reference:

PSA Lower, CMC 3.5# Trigger, Magpul ACS Carbine Stock, ASC mag, 16" BCA SS M4 Barrel, Primary Arms 2.5x Prism Scope w/ ACSS Reticle.
I started with 4 boxes of Hornady 6 mm ARC 108 ELD-M just to get a feel for the rifle upper & barrel. It ran well, no hiccups.
Cleaned, resized w/ RCBS small base die, trimmed to spec, prime w/ CCI small rifle primer .
Recipe: 108 Grain Hornady ELD-M Bullets over 27.5 grains of Accurate 2520 Powder.
Average Velocity was 2350 +/-.
Good Accuracy.
No signs of over pressure.
Will increase to 28 grains of the same Accurate 2520 and load up 20 more of these and hopefully get above 2400 fps. with good accuracy.
Hodgdon provided loads for 107 and 110 grain bullets. I used the 110 grain load as my guide.
I'll follow up with results with better specifics regarding velocity and pics of accuracy.

 

[olszta]

I thought I'd add the following for 6 ARC, AR15 reference:

PSA Lower, CMC 3.5# Trigger, Magpul ACS Carbine Stock, ASC mag, 16" BCA SS M4 Barrel, Primary Arms 2.5x Prism Scope w/ ACSS Reticle.
I started with 4 boxes of Hornady 6 mm ARC 108 ELD-M just to get a feel for the rifle upper & barrel. It ran well, no hiccups.
Cleaned, resized w/ RCBS small base die, trimmed to spec, prime w/ CCI small rifle primer .
Recipe: 108 Grain Hornady ELD-M Bullets over 27.5 grains of Accurate 2520 Powder.
Average Velocity was 2350 +/-.
Good Accuracy.
No signs of over pressure.
Will increase to 28 grains of the same Accurate 2520 and load up 20 more of these and hopefully get above 2400 fps. with good accuracy.
Hodgdon provided loads for 107 and 110 grain bullets. I used the 110 grain load as my guide.
I'll follow up with results with better specifics regarding velocity and pics of accuracy.

Again for the record using the afore stated rifle specifics, here are the results of 10 rounds of reloaded 108 gr Hornady ELD-M bullets over 28+ grains of Accurate 2520 powder (I spooned the powder into the RCBS scale...the SD is a bit sloppy as I was trying to get an idea of what 28 grains and just a bit more powder than 28 grains would produce for velocity):

2506
2461
2516
2493
2519
2482
2492
2479
2468
2495

24911 ÷ 10 = 2,491 fps average for 28+ grains of Accurate 2520 powder vs previous loads of around 27.5 grains which yielded in the 2350 fps velocity range. Note: I'm using a Caldwell Ballistic Chronograph Premium Kit to obtain velocity readings.

The ballistic advantage site says this about 6 mm ARC and barrel length:

"Based on our experience and feedback from other shooters, 16 to 18 inches is the ideal 6mm ARC barrel length if you want a gun that does it all. In fact, according to Hornady, 18 inches is the optimal barrel length for military applications.

Versatility is crucial for a military gun because the weapon needs to be easy to carry during close to mid-range combat and when traversing various terrains. A 16 or 18-inch 6mm ARC barrel checks these boxes without compromising muzzle velocity.

Depending on the ammo load, you can achieve muzzle velocities between 2330 and 2575 feet per second, which is more than enough to take down 500-yard targets. The range and mobility of the barrel make it suitable for home or self-defense and anyone dabbling in hunting or target practice." see https://www.ballisticadvantage.com/...xt=A 16 or 18-inch,take down 500-yard targets.

My recent albeit minimal experience confirms the above quote from Ballistic Advantage. Accuracy was good at 200 yards. I'm really enjoying the 6 mm ARC in the AR 15 platform.

 

[FuhQ]

Like has been said... Your load is too hot. Back it down 1 to 1.5 grains and rework your ladder.

I'm running a 16" bolt gun in 6 ARC, and with a Nosler 115 RDF, 29.5 gr Lever, Hornady brass, and CCI 400's, i'm running them at 2,575 FPS MV. And that load is VERY hot (work up with caution) with the 115's.

 

[FuhQ]

Again for the record using the afore stated rifle specifics, here are the results of 10 rounds of reloaded 108 gr Hornady ELD-M bullets over 28+ grains of Accurate 2520 powder (I spooned the powder into the RCBS scale...the SD is a bit sloppy as I was trying to get an idea of what 28 grains and just a bit more powder than 28 grains would produce for velocity):

2506
2461
2516
2493
2519
2482
2492
2479
2468
2495

24911 ÷ 10 = 2,491 fps average for 28+ grains of Accurate 2520 powder vs previous loads of around 27.5 grains which yielded in the 2350 fps velocity range. Note: I'm using a Caldwell Ballistic Chronograph Premium Kit to obtain velocity readings.

The ballistic advantage site says this about 6 mm ARC and barrel length:

"Based on our experience and feedback from other shooters, 16 to 18 inches is the ideal 6mm ARC barrel length if you want a gun that does it all. In fact, according to Hornady, 18 inches is the optimal barrel length for military applications.

Versatility is crucial for a military gun because the weapon needs to be easy to carry during close to mid-range combat and when traversing various terrains. A 16 or 18-inch 6mm ARC barrel checks these boxes without compromising muzzle velocity.

Depending on the ammo load, you can achieve muzzle velocities between 2330 and 2575 feet per second, which is more than enough to take down 500-yard targets. The range and mobility of the barrel make it suitable for home or self-defense and anyone dabbling in hunting or target practice." see https://www.ballisticadvantage.com/blog/what-is-the-best-barrel-length-for-6mm-arc/#:~:text=A 16 or 18-inch,take down 500-yard targets.

My recent albeit minimal experience confirms the above quote from Ballistic Advantage. Accuracy was good at 200 yards. I'm really enjoying the 6 mm ARC in the AR 15 platform.

AR data doesn't apply here... Bolt guns handle much more pressure than AR's. AR load data for 6 ARC is totally different in pressure ratings, and will always be LOWER charge weights than with a bolt gun.

 

[Jdowns0415]

I used the 6ARC gas gun data with lever and I was blowing primers/bulging the cases and getting the belt around every cartridge and the FPS was 100-200 FPS over the stated velocity with my 18 inch barrel. It was 110 degrees outside and the ammo was sitting outside in the sun in the bed of my truck. I stopped using lever evolution and started using VARGET and STABALL match. Lever might work better when its cooler in texas but in the summertime max charges are a no go. In the winter time I will probably use it again but back the charge off by .8 so I dont ruin more brass

 

[olszta]

Again for the record using the afore stated rifle specifics, here are the results of 10 rounds of reloaded 108 gr Hornady ELD-M bullets over 28+ grains of Accurate 2520 powder (I spooned the powder into the RCBS scale...the SD is a bit sloppy as I was trying to get an idea of what 28 grains and just a bit more powder than 28 grains would produce for velocity):

2506
2461
2516
2493
2519
2482
2492
2479
2468
2495

24911 ÷ 10 = 2,491 fps average for 28+ grains of Accurate 2520 powder vs previous loads of around 27.5 grains which yielded in the 2350 fps velocity range. Note: I'm using a Caldwell Ballistic Chronograph Premium Kit to obtain velocity readings.

The ballistic advantage site says this about 6 mm ARC and barrel length:

"Based on our experience and feedback from other shooters, 16 to 18 inches is the ideal 6mm ARC barrel length if you want a gun that does it all. In fact, according to Hornady, 18 inches is the optimal barrel length for military applications.

Versatility is crucial for a military gun because the weapon needs to be easy to carry during close to mid-range combat and when traversing various terrains. A 16 or 18-inch 6mm ARC barrel checks these boxes without compromising muzzle velocity.

Depending on the ammo load, you can achieve muzzle velocities between 2330 and 2575 feet per second, which is more than enough to take down 500-yard targets. The range and mobility of the barrel make it suitable for home or self-defense and anyone dabbling in hunting or target practice." see https://www.ballisticadvantage.com/blog/what-is-the-best-barrel-length-for-6mm-arc/#:~:text=A 16 or 18-inch,take down 500-yard targets.

My recent albeit minimal experience confirms the above quote from Ballistic Advantage. Accuracy was good at 200 yards. I'm really enjoying the 6 mm ARC in the AR 15 platform.

Latest results using Hodgdon maximum recommended Accurate 2520 load for 6 ARC for a 110 grain :

108 gr ELD-M Bullets over 28.4 grains of 2520 yielded consistent 2,510 to 2,530 fps ouf of the 16 inch SS barrel with 1:8 twist.
This agrees with the Ballistic Advantage quote in my earlier post. Hornady Calculator has it going subsonic at just past 1,100 yards.
Accuracy was excellent, at least for my skill level. Call it MOA at 200 yards. I shot 10 round groups.
I'll use this load and work at the 400 (furthest out range we have) for consistent and hopefully improved accuracy.

 

[CollarChoke]

As another data point on the Hornady Lever numbers, in a 20" 1:7.5 Benchmark barrel on an Origin Action I was also seeing higher than expected velocities and early pressure signs (shiny ejector marks, no other signs) with Hornady's LeverEvolution bolt gun loads in 75 degree weather using both Hornady and Alpha brass with CCI BR4 primers and 108gr eld-m bullets, loaded to factory specs seating wise.

At 31.2gr I was running 2890fps out of a 20" which, while exciting, seemed too good to be true.

Some helpful folks on here as well as my barrel provider ran QuickLoad numbers for my loads which indicated I was running very high pressures at the 31.2gr max suggested by Hornady. Way past the 62000psi mark that Hornady says is the max for 6ARC bolt gun loads.

So if you're reading this and planning on following Hornady's recommendations as a starting point, stay way below the 30gr number and work your way up, stop when the velocities don't make sense for your barrel length and keep a close eye on pressure signs.

I'm going to start over and aim for 2750fps result which I hit around the 29.7gr of LeverEvolution mark during my ladder testing.

I think Hornady should revise those Lever numbers or at least put a big ol' asterisk on them for people that use their data as a presumed safe starting point.