Still cant figure this rifle out. 300 AAC

[adanymous]

background info: Ive been trying to get this gun to shoot but Im having no real luck. Im casting the NOE 311 247 and putting it on 10.3 gr 4198, and it is subsonic. The gun is a rem 700 SPS tactical in 300AAC. I was shooting the bullets without weight sorting, and I have pretty good 25 and 50 yd results, but not great. It shoots around 1.5 inch at 50, usually, with quite a few fliers. Im sizing to 311 I think, well whatever my bore slugged out to. And im using the NOE neck expander thing that someone here recommended. And a lee FC die set pretty dang light, just enough to de bell the case and get it against the bullet.

I was shooting this rifle yesterday, trying to dope it out to crazy long range for a subsonic....because shooting is fun. My groups were as stated above. But when I got it back to 150 and 200 I was shooting 3 inches or so, with some flyers going to maybe 4.

I knew I could make some better stuff, so I pulled out some bullets I cast a while back, sized them, and seperated by weight. My mould throws them from 245 at the low to 251 high. I loaded 100 between 246.5 and 247.5. I know thats a big range but I was just trying it out to see what kind of difference it made. I also neck turned 100 pieces of brass, as I thought the thickness from cut down 223 might be causing issues. So I uniformed them to .001 on an rcbs neck turning tool. I went to the range and shot 50 of the 100, and my 200yd group was about the same as yesterday. My 100 yd group was just as bad, and really didnt show any consistency. Bullets were drifting from left to right in a straight line for 3 inches. definitely not a group anyone would be proud of. I was shooting all of the groups from the prone, off of a bipod. I dont really know what else to try to tighten up these groups. My bullets are so long they dont feed very well into the chamber, and they are just a couple thousandths back from engaging the rifling when chambered, I actually had to quit shooting today because I had a bad primer and when I tried to eject the cartridge the bullet stayed in the bore. Mustve missed the crimp with that one. The only weird things I am seeing is that the case necks are usually very sooty after the bullets are fired, and the case mouths are a bit rough after they have been fired, and some will have a slight burr or small brass shaving still attached.

I could use any help you guys can offer. Im not sure what else to do. I am no master reloader so any tips, or suggestions are welcome.

Ive heard the hogue stock is pretty detrimental to accuracy, so I ordered the magpul hunter stock for it today. But that would have to have a pretty amazing effect to fix the issues Im having.

[NavyVet1959]

Just blame it on the wind and have another beer. That always works for me...

Seriously though... Here's an example, treating it like you would wind correction for aircraft or current correction for boating...
A 5 mph wind change in wind speed is 7.333 fps (= 89.6667 inches-per-sec).
A bullet that averages 1000 fps takes 0.3 seconds to travel 100 yards.
Thus the 5 mph wind change could result in a horizontal change in point of impact of 26.9 inches.

So, blame it on the wind and pop the top on another beer...

As pointed out later in this thread though, bullets don't quite work that way, but at least this gives you an idea of how much wind *could* affect an object...

[Yodogsandman]

"I am seeing is that the case necks are usually very sooty after the bullets are fired, and the case mouths are a bit rough after they have been fired, and some will have a slight burr or small brass shaving still attached."

Soot on the case necks is normal for low pressure rifle loads. Maybe try a faster burning powder.

Finding roughness, burrs or brass shavings on the case mouths is NOT normal. Do a pound slug of your chamber and find out what your overall trim length should be for your cases. They may be too tight and when you chamber a round, pinches the case mouth to the boolit. A DANGEROUS condition with jacketed bullets and most times with cast boolits at high pressure. It prevents the boolit from being released from the case mouth when fired, causing excessive pressures. At the least, it's destroying your boolit. Probably resizing it and causing gas cutting.

Also, when you do a pound slug of your chamber, check the size of your throat and size your boolit to the throat size instead of bore size.

Are you using a gas check?

[runfiverun]

I'm gonna take a stab at it being the Bi-Pod.
you have to load the Bi-Pod up the same way every time.
I usually don't shoot off one but when I do I make sure I pull it fully to the rear in a straight line.
if your off a little bit it will torque the shot to the side or bounce and throw the shot high.
you want the legs under pressure so that they slide backwards without any flex in them.

[MarkP]

I have a similar rifle (Rem SEVEN Micro AAC) and the same NOE mold; with H-110 mine shoots similar to yours at 175 yds. (3") at 75 yds under 1".

Did you de-burr your case mouths and screw the NOE expander down far enough to put I slight bell on the mouth?

[popper]

BO is a different beast. Size to throat if you can & keep from hitting the groove. Load the bipod, I push forward to load it.

[adanymous]

Size to throat if you can & keep from hitting the groove. .

Can you explain this whole sentence please. I do de-burr. And I do bell the case just a bit. Im not terribly concerned with the bipod but that could be it. I think yodog might be right. I trimmed these to min saami though. I use a ce or something similar trimmer. Its a big motor with an end mill chucked up in it. Uses some delrin bushings that fit the case shoulder and set the length. Its fantastic for huge trim jobs, and accurate. But I will definitely check my work on that too. Thanks for the tips guys. Please keep em coming. I REALLY want this gun to shoot.

The case mouths are pretty uneven after firing. And rougher than any other cases I shoot.

[Digital Dan]

Just blame it on the wind and have another beer. That always works for me...

Seriously though... Here's an example...
A 5 mph wind change in wind speed is 7.333 fps.
A bullet that averages 1000 fps takes 0.3 seconds to travel 100 yards.
Thus the 5 mph wind change could result in a horizontal change in point of impact of 2.2 inches.

So, blame it on the wind and pop the top on another beer...

Hey Navy, not that it has much to do with anything, but your method of calculating wind drift is out in left field. Sorta works that way for round balls, but has nothing at all to do with how conical bullets perform. The more productive way to examine wind effects is to think about it in terms of bullet drag.

The formula used back when men were steel and ships were wood:

D=W(T-Tv)

Where:
D= deflection in feet
W=Wind velocity across the range in fps
T= Time of Flight for a specified distance
Tv= Time of Flight for the specified distance in a vacuum

It is a fair approximation of what to expect, but not precise. It incorporates BC/Drag in the calculation. Other 'puter programs are likely more precise, but hey, this is where it started. Wind "drift" is not drift, but a deflection. The largest influence of wind occurs at the muzzle, not down range. Just to cloud things a bit, drag coefficients/BC change with velocity for a given form. 'Tis a world only a math professor could love.

[Fishman]

That is a wide weight range for your cast. Preheat your mould on a hot plate and make sure you run your pot at a consistent temp of around 725-750. Inspect them to make sure the edges of your bands and the base are sharp and defined. You should easily get them all within a grain weight-wise if you do this. The wide variance in weight is the symptom that something is wrong with your bullets, not the cause of the problem. Don't be afraid to throw questionable bullets back in the melt until they come out sharp and lightly frosted.

[adanymous]

That is a wide weight range for your cast. Preheat your mould on a hot plate and make sure you run your pot at a consistent temp of around 725-750. Inspect them to make sure the edges of your bands and the base are sharp and defined. You should easily get them all within a grain weight-wise if you do this. The wide variance in weight is the symptom that something is wrong with your bullets, not the cause of the problem. Don't be afraid to throw questionable bullets back in the melt until they come out sharp and lightly frosted.

I do all of these things.

[Mica_Hiebert]

I would try a lighter bullet in the 200-220 grain range. You may be experiencing a stability issue depending on your barrel twist, what are your extreme spreads in velocity? Also try seating deeper and jumping to the lands a little bit even tho this goes against how your supposed to load cast bullets in a rifle every gun is different and there are no deffinates in hand loading...

[NavyVet1959]

Hey Navy, not that it has much to do with anything, but your method of calculating wind drift is out in left field. Sorta works that way for round balls, but has nothing at all to do with how conical bullets perform. The more productive way to examine wind effects is to think about it in terms of bullet drag.

The formula used back when men were steel and ships were wood:

D=W(T-Tv)

Where:
D= deflection in feet
W=Wind velocity across the range in fps
T= Time of Flight for a specified distance
Tv= Time of Flight for the specified distance in a vacuum

It is a fair approximation of what to expect, but not precise. It incorporates BC/Drag in the calculation. Other 'puter programs are likely more precise, but hey, this is where it started. Wind "drift" is not drift, but a deflection. The largest influence of wind occurs at the muzzle, not down range. Just to cloud things a bit, drag coefficients/BC change with velocity for a given form. 'Tis a world only a math professor could love.

My calculation was based on what you see with aircraft -- if the air is moving X mph at a 90 degree angle to your direction of flight, you can expect to be X miles to the side after 1 hour. The rounded shape of a bullet could result in less wind resistance from the side which could make it drift a bit less for a given crosswind component.

[popper]

NOE 311 247 - I assume FB version, lots of base below the 'shoulder'. BO has a long throat, you may be expanding the nose during seating to where it sticks in the throat - not groove. Happened to me 3x last trip & I shoot 145gr.. I neck turn 0.0012" & notice after a few loadings of a case the mouth gets a little ragged - few flakes of brass hanging on them. Doesn't make any difference. My boolits don't have a crimp groove - crimping tight in the groove may work the mouth more. I do think bipod 'jump' is your main problem.

[Nicholas]

I share Mica's opinion. That weight bullet in a 30 caliber has to be a long bullet and at subsonic velocities fairly easy to lose stability. It would require a steep twist to stabilize.

[Digital Dan]

My calculation was based on what you see with aircraft -- if the air is moving X mph at a 90 degree angle to your direction of flight, you can expect to be X miles to the side after 1 hour. The rounded shape of a bullet could result in less wind resistance from the side which could make it drift a bit less for a given crosswind component.

I understood that, merely letting you know that is not how it works in the world of bullets and crosswinds. The methodology for bullet drift calculation is counter intuitive. Is what happens when one introduces gyroscopic stability and variable drag coefficients into the equation. As I suggested above, you methodology works for round balls. It does not work even a little bit for conical bullets.

See the following:

http://www.nennstiel-ruprecht.de/bullfly/
http://www.nennstiel-ruprecht.de/bullfly/fig5.htm
http://appliedballisticsllc.com/ballistics/

[adanymous]

The rifles twist is 1-7, and per previous discussions about this gun and bullet combo, I should be in fine shape there. But if my new stock doesnt fix the issue I may try to bum a couple boolits to try out...volunteers line up here.

[MT Chambers]

Definitely ditch the crimp die, it is a detriment, my most accurate load in the .300 is with the NOE copy of Eagan's Mx-2, but not a subsonic speeds. I don't have my info with me but I believe I use 17.5 gr. of RL-7.

[NavyVet1959]

http://appliedballisticsllc.com/ballistics/

Hmmm... Interesting calculator to play what-if scenarios with...

[adanymous]

Definitely ditch the crimp die, it is a detriment, my most accurate load in the .300 is with the NOE copy of Eagan's Mx-2, but not a subsonic speeds. I don't have my info with me but I believe I use 17.5 gr. of RL-7.

Id love to drop the crimp,its an extra step, but if I do how do I get the case flush with the bullet? After I run it through the seat die there is still a little bell.

[NavyVet1959]

Id love to drop the crimp,its an extra step, but if I do how do I get the case flush with the bullet? After I run it through the seat die there is still a little bell.

Nothing wrong with using the FCD, just don't get too aggressive with it.I find it

I find it a lot easier to separate the seating and crimping stages into two stages instead of having them done at the same time. I could have done this by buying another seating and crimping die and removing the seating stem from it, but I went with the FCD instead.