300 BLK MATCH Ammo that is good out to 800 Yards...

[Dr.Phil]

Thanks for the kind words guys.

I would like to point out a few things though.
First and foremost, this almost certainly would not have happened without dellet.
In fact, I loaded up some with AA#9 from the old Sierra Whisper(r) data and those would have likely destroyed my gun.
Dellet ran those through Quick Load and identified the danger and I was able to just pull those.

No, this is not "Fake News" or some other trolling effort.
These results are real and with careful load development, anyone should be able to duplicate these results.

Yes, I do realize that the bullet is going transonic at those distances.
I believe that the 1:7 twist rate and the design of the G9 allow it to transition without falling out of the sky like a 168 Match King in 308.
(That is why my original goal was 600 yards.)

As far as components go, primer substitution is not a problem, case selection is very important, and powder is critical.
No, H110 and W296 are not the same.
They are very similar and you could use H110, but W296 will work better. (Lots of science there, dellet can elaborate.)

This project started off as a silly notion and due to the quality of the membership on this forum, unheard of results were achieved.
That is one of the reasons that I felt compelled to make this project public.
I have seen similar efforts stay behind closed doors in the 308 Win world and there is not a reason to do so. (ex. 155 Lapua Scenar @ 3,000 fps)

\\BZ\\

[Bob the nailer]

This is excatly why I hang around this site, to absorb this kind of stuff! Again excellent work.

[dellet]

A couple of things to add as far as load work up and rifle components. I bought a Remington 700 a few years ago when Walmart chose to blow them out, instead of deal with the trigger recall. Some of the best money I have ever spent. I did a thread a couple years back "extreme Blackout" about pushing the limits. That 700 has taken a beating, but I found some limits.

Dr. Phil did not include a very important component in his rifle. It's an LMT enhanced bolt carrier group. It's designed to slow down unlock time of the bolt, and the bolt face fully supports the case head. No half moon from the ejector. This one component costs more than a lot of folks put in their whole rifle. It basically allowed him a half grain of powder on the top end.

He talked about brass choice.
I sent him a handful of brand new PNW brass that I bought when they went out of business to try. We possibly found out why they went out of business. One round down range and he has some perfect brass to use for subsonic loads, and a trophy to put on the bench to remind him to look a gift horse in the mouth.
Sometimes free ain't worth it.

I get on a soap box every time people talk about drilling gas ports. The Doc's port is small buy Internet standards. Just right according to Noveske, and over gassed, suppressed with this load. This would not have been possible running pistol gas and a .125" port, probably not even a .105".

Not to make too much of a look at me statement, but more of a "this is how five years of work looks easy when you finally let the cat out of the bag" kind of thing.

I worked up up the load Dr. Phil used with basically 10 bullets. There was a question of how brass would react to pressure.

I went straight to max load with 7 different powders using the 700. Three of those powders are not listed in Quickload's data base that I have.

Ran the top two performers, highest velocity, least pressure signs in a 10.5" AR with a slight powder adjustment up. Then the best of those two, was given one more run to confirm the load and velocity.

What allowed this to work was a lot of swipes, stiff bolts and a few popped primers in the past, with hands on testing. No load book or computer program out there replaces actually pulling the trigger. I will say, that after a while using those tools, they will give a good indication of when to use a string.

This cartridge is capable of far more than people think. It just takes working outside the box.
Somebody should do a thread with that title

As a closing thought I really did not know the size of target Dr. Phil was shooting at. When he sent a message telling me he was shooting steel at 800 yards, I thought he was down at the Navy base taking pot shots at an aircraft carrier. I had to look up the size of his target.

Basically hitting a piece of notebook paper from 3-800 yards, one shot at a time.

Any one who has been to the range this time of year, or helped with a hunter sight in day, knows this is well above the average display of skills.

[Bob the nailer]

. I did a thread a couple years back "extreme Blackout" about pushing the limits.

Have a link to this ?

[7mmShooter]

That's awesome, very well done gentlemen! If they weren't so expensive, the Warner 155gr Flatlines would be quite a step up in performance I would think.

[Sharkbite]

Wait....WHAT? 300blk only goes 100yds and then turns into a falling brick. I know cause i read it on the interweb thingy.

Seriously, thanks guys for continuing to push the envelope with this cartrige

[dellet]

. I did a thread a couple years back "extreme Blackout" about pushing the limits.

Have a link to this ?

Extreme Blackout
viewtopic.php?t=96500

Working outside the box
viewtopic.php?t=99464

Some of the escapades that were part of the journey.

[Bob the nailer]

Thanks, really like reading up on this stuff. I had really good results working on a load for my 22-284 a few years back.

[Dr.Phil]

Dr. Phil did not include a very important component in his rifle. It's an LMT enhanced bolt carrier group. It's designed to slow down unlock time of the bolt, and the bolt face fully supports the case head. No half moon from the ejector. This one component costs more than a lot of folks put in their whole rifle. It basically allowed him a half grain of powder on the top end.

Thanks for adding the additional detail!
The LMT e-BCG and other details slipped my mind.
Being an engineer, I am a bit nutty at over engineering my builds, down to EVERY component.
This typically is not for over 90% of most users since the benefits are not visible or understood by the average bear. (and the additional cost is significant...)

For those that have never heard of this product, here is some more info on the LMT e-BCG.
Taken From: http://www.m4carbine.net/showthread.php?t=3379

Let us perhaps be a little more precise with regard to the details of the LMT enhanced bolt and carrier system. As shown the details are very often misinterpreted.

In the first instance one must understand why the system exists, more particulaly in the context that the design is brilliant in its execution, but as reported frequently on the errornet is not always reliable. The design basis for the assembly is specifically to enhance the durability of the M4 configuration as currently issued. This gun is to some extent unbalanced. Port pressures running military grade ammunition are well in excess of the design levels which leads to very high carrier acceleration rates (+22 f/s/s). this combined with chamber pressure drop often creates the undesirable condition that the bolt commences to unlock while still subject to a degree of head thrust from the cartridge case. The result is that the lugs are subject to a biaxial loading of both shear and bending.

The LMT system being both the carrier and the bolt seeks to operate directly in this gun and elleviate symptoms. The carrier is set up with a longer delay during the initial portion of its movement. To facilitate this longer cam path and movement of the bolt forwards in the carrier, the front edge of the carrier is extended such that it still continues to retain the extractor pivot pin. Additional exhaust vents act to drop the piston pressure faster and to relieve any blowby at the tail of the bolt.

The bolt itself is of particular interest. The function of the dual spring extractor is frequently misinterpreted as an attempt to add spring force to the extractor claw. Rather it reduces the fatigue that the extractor spring(s) undergo by allowing the use of longer springs with lower K values; the % relative compression during the movement of the extractor is reduced. Remember that additional extractor force is not required now that the carrier is slowing the extraction cycle. The mitigation of stress in the bolt is accomplished in several ways. Material is the least visible change but is important to the design. The traditional Carpenter 158 is abandoned, being replaced by a significantly tougher grade from a different manufacturer. The lugs themselves are generously radiused between lugs and at the rear the diameter is actually reduced to allow a larger transition radius to be machined. The incorrectly identified sand cuts on the lugs are stress relief cuts. These allow any individual lug to elastically deform and give a smoother load over the contact patch. While this type of feature is very difficult to calculate and even more difficult to implement it helps to place the lug in a true shear load rather than amplify the bending moment. As noted the lug opposite the extractor is relieved. This feature prevents the unequal transfer of load to the two opposite lugs but I would argue that the stress relief groove already in place largely accomplishes this purpose. This is a academic quibble so I will bow to LMT in this respect. There is one additional feature that can be found in the bolt, but I am not at liberty to disclose the detail.

When considering wether to use the LMT parts one must consider the weapon. Correctly ported guns will derive little or no benefit from a carrier that is specifically set up to absorb excessive port pressures and some degree of residual case pressure. If not sufficiently gassed the reliability will suffer. This is not a fault of the carrier rather a mistake made in the application so be careful with simple substitutions. The bolt itself is exemplary. If not constrained by a $ value the bolt is a worthy addition to any rifle and will do nothing but enhance the durability of this part of the system.

Bill Alexander

Like dellet said, the LMT e-BCG can be a double edged sword when doing development.
Since it unlocks much later and has a fully supported bolt face, pressure signs are not obvious.

This is one component that is not optional in any of my builds.
Its only detractor is cost, everything else is a net gain:
- Reliability
- Durability
- Accuracy
- Reduced wear on the entire platform

The only ones that I have ever seen fail are from KBs resulting from non BCG errors.
(I'll let dellet elaborate if he wishes to...)

[dellet]

Like dellet said, the LMT e-BCG can be a double edged sword when doing development.
Since it unlocks much later and has a fully supported bolt face, pressure signs are not obvious.

This is one component that is not optional in any of my builds.
Its only detractor is cost, everything else is a net gain:
- Reliability
- Durability
- Accuracy
- Reduced wear on the entire platform

The only ones that I have ever seen fail are from KBs resulting from non BCG errors.
(I'll let dellet elaborate if he wishes to...)

It's quite possible the LMT saved my face.

No secret I push the envelope, and I can honestly say that has never resulted in any more damage than maybe a broken extractor, when brass had to be forcibly removed from a bolt.

What almost got me killed was a lack of attention on the loading bench. Somewhere in the range of 12-14 grains of #9 under a 190 grain bullet, estimates out around 125-130K for chamber pressure.

I salvaged the forward assist and dust cover from the upper. No Damage to the lower.

Barrel extension cracked. Bolt carrier split where it tried to pull itself out around the cam pin. It looked like the barrel in an Elmer Fudd cartoon.

Thread was called something like "reloading and distractions don't mix", might be worth a bump. All I did was turn around and answer a question. That led to a double charge being dropped.

I still occasionally pop my head up off the scope if something does not feel right, like much heavier trigger than i'm used to and it's been 2 maybe 3 years.