A Problem with the NOE .309 129grn in the .300 AAC Blackout

[klcarroll]

Hi

I have a little 10" barreled .300 AAC AR that has always been a pretty good shooter with handloads featuring 147 grn FMJBT surplus J-Words. (1.5" at 50 yards)

I recently picked up a NOE 129grn mold in the hope of coming up with a really cheap plinking load for this weapon. This boolit is a gas check, spire point design that loads to a decent overall length, and feeds reliably from an AR mag. (For info on this boolit see: http://noebulletmolds.com/NV/product...roducts_id=763)

Everything is good, .....except for the fact that it is all over the paper at 50 yards. I'm seeing 12" groups when I expected to see 2" - 3" groups!!

According to my chronograph, I'm getting about 1900 fps, which is comparable to the velocity I load the 147grn FMJBT rounds to.

.....So what do you think? .....Is the fast twist (1:8) of the .300 AAC barrel "over-stabilizing" this boolit? Has anyone else had similar problems with light .309 spire points???

KLC

[GoodAlloy]

What's your alloy hardness? This bullet has no bore ride & must be hard to run in a 1-7 or 1-8 twist

[GoodAlloy]

Try as hard a alloy as you can muster & use as slow a ball powder as you can that at all gives you decent velocity

[klcarroll]

Thank you for bringing up the issue of hardness!! .....That might be the answer.

I cast these little 129grn guys out of the same alloy I use for my Lee 155 and 230 grn .309 boolits: ....That alloy is basically just a good hard water quenched wheel-weight alloy. It could very easily be too soft for this boolit design!

....Anybody have ten pounds of lino that they want to sell??

KLC

[dh2]

I have heard to many bad things about this NOE mould , So I went a different route with an ACE group buy , an I do prefer a Bore rider any way, I got it this week hoping to see how it goes.
http://castboolits.gunloads.com/show...dweight-boolit

[Ford SD]

Hi

I have a little 10" barreled .300 AAC AR that has always been a pretty good shooter with handloads featuring 147 grn FMJBT surplus J-Words. (1.5" at 50 yards)

I recently picked up a NOE 129grn mold in the hope of coming up with a really cheap plinking load for this weapon. This boolit is a gas check, spire point design that loads to a decent overall length, and feeds reliably from an AR mag. (For info on this boolit see: http://noebulletmolds.com/NV/product...roducts_id=763)

Everything is good, .....except for the fact that it is all over the paper at 50 yards. I'm seeing 12" groups when I expected to see 2" - 3" groups!!

According to my chronograph, I'm getting about 1900 fps, which is comparable to the velocity I load the 147grn FMJBT rounds to.

.....So what do you think? .....Is the fast twist (1:8) of the .300 AAC barrel "over-stabilizing" this boolit? Has anyone else had similar problems with light .309 spire points???

KLC

From my reading here and Experience with the 300 black and 308 win in cast you are pushing it too fast-- you need to slow it down
the problem then is do you have enough gas at that point to work the action with the light wt bullet
if you had a bolt gun you could shoot it at slower velocities and not have to worry about gas working the action

if you had a different barrel twist 1-10 /1/12 it would be better at that velocity

Jacketed you do not have the same problem (as jacketed bullets are balanced better / shaped differently) and can be pushed faster

With cast you have to slow it down or go to a heaver bullet and slow it down

[wordsmith]

By my calc's, you're running about 171k RPM's, which exceeds the generally accepted 140k limit. You may need to drop your velocity under 1600 fps to get accuracy back.

http://castboolits.gunloads.com/show...velocity-chart

[Artful]

That's a wicked looking boolit


but with that shape it needs hard alloy just to keep the nose straight.

this one works ok in my SKS (7.62x39) which as something like 1:9 or 1:10 twist rate barrel

http://noebulletmolds.com/NV/product...products_id=71


and I googled SKS twist it's supposed to be
'Direction & rate of rifling twist - Right, 1 turn in 9.45 inches'

[Artful]

this might help ya
http://castboolits.gunloads.com/show...f-Death-report

http://www.300blktalk.com/forum/view...9400&hilit=NOE

http://www.300blktalk.com/forum/view...0339&hilit=NOE

[longbow]

Which of the above boolit moulds do you have?

When I saw the subject line I was thinking the NOE 0.314" x 129 gr.

I have that one for my .303's. I had an issue with the neck sizing being too tight for the larger boolit and the very small bearing surface of driving bands being swaged down by the necks. Both case neck annealing and doing less neck sizing solved my accuracy issues with it.

In my case, I lapped the mould to 0.316" to suit my Lee Enfields throats which like 0.315" but the RCBS dies were sizing back to suit 0.311" boolits so the necks were very tight. I went to Lee collet sizer and now beck size to 0.002" under boolit diameter.

You might try pulling a couple of Boolits and mic'ing them to check diameter after seating. If the necks are tight you might be swaging those narrow driving bands down.

Also, what the other guys said about hardness and for the same reason... small driving bands. At the velocity and twist you have you may find the boolits skid a bit. Harder is better.

Just a couple of thoughts.

Longbow

[xacex]

Poor design, doesn't work.

10-4 good buddy. I believe this is about the answer I have as well. I like the Mihec 311410 with a hollow-point, and gas check. So far under 2" at 100 yards with a 130 grain boolit powder coated. That is running at 2170 FPS with H110 out of a 16"er. I need to do some more work with it, but not bad for a cast boolit weighed within a grain, homemade gas checks, cases were freebies converted by me, and all loaded on a progressive. As they say "good enough for government work" but it is actually twice as good as required by uncle Sam.

[45 2.1]

.....So what do you think? .....Is the fast twist (1:8) of the .300 AAC barrel "over-stabilizing" this boolit? Has anyone else had similar problems with light .309 spire points??? KLC

Another member here and I have been shooting the MP 311-410 HP in a 300 AAC AR-15, 8 twist at that. It groups about 1.5" at 100 yards at somewhere about 2,000 fps without load development yet, just a load picked out of the book. I would say the twist pundits don't have it right, but that's your call for your stuff. It is a lot more important that the boolit fit and be at the proper hardness for the alloy used than anything else.

[GoodAlloy]

I believe that the further you get away from the rotational spin of 140,00 RPM the more important fit and hardness becomes. 140,000rpm does seem to be a limit on typical cast use in typical situations. We do what we do because it is interesting and educational which leads to better results for everyone. Think of all the help we have because some intrepid soul dared to "give it a try". I really like this design if for no other reason than the tinker factor. We should try to push the limits.
Go hard alloy with a fit that is at least .001" bigger than the throat and use as slow a powder as will give the desired velocity. The slow power is key for two reasons. First it allows function in auto loader due to gas volume and then actally more important it provides a filler effect without the filler. The power acutally acts as filler. Gentle push into the rifling and continues to push all the way out. I believe that the point as which you see some (a little bit) of unburnt powder you are in the right zone. I am currently pushing this design at 1700fps out of a 16" gaser & getting right at 2" at 100yrds. I am using BRN#30 with copper in it. I am using AA2200 powder. It feeds and functions awesome to say the least. Don't give into the easy road, Keep playing guys, its how we all will better ourselves.

[GoodAlloy]

Oh forgot to mention it is a 1-8 twist S.S barrel, carbine gas system, 5R rifling

[GoodAlloy]

Well guys, while I am on my soap box. One more thing. I have a therory.... True hardness all the way through the core of the bullet will give you better rotational rifling grip than heat treating will. Heat treating is easy and works real well for control of friction, powder temp., and gas cutting (to a degree). However, it really does not solve rifling striping due to being softer as you move from the perimeter of the boolit to the center. True hardness all the way through gives much better rifling grip when dealing with high velocity in a fast twist. I say therory because all of my testing has not been documented other than in my head. I will say that from all the testing that I have done I am conveinced that it is a fact...Well at least in my head anyhow.

[Wayne S]

two things you didn't mention; what the throat on this bbl. sluged at and what you are sizing your bullets at ??

[xacex]

Another member here and I have been shooting the MP 311-410 HP in a 300 AAC AR-15, 8 twist at that. It groups about 1.5" at 100 yards at somewhere about 2,000 fps without load development yet, just a load picked out of the book. I would say the twist pundits don't have it right, but that's your call for your stuff. It is a lot more important that the boolit fit and be at the proper hardness for the alloy used than anything else.

It is not a bad boolit to say the least. I am running it in a 7 twist right now so the rpm is even greater. Sized right even straight wheel weights with no water quenching seems to work. I did not see any appreciable gains from water quenching at this RPM as far as accuracy. Who knows, maybe the powder coat keeps it together better. I would not use it on any game I wanted to eat due to the impact reacting like a varmint grenade. I imagine a modification to the NOE to include a small meplat would help with its accuracy issue. The nose bending is something that concerned me in the design for a semi auto, and my concerns were validated. If it had a meplat, and a hollow-point I think it would shoot as good as the MP 311-410, but then we are only talking about changing the nose ogive to a TC at that point. What would be the benefit if any?

It would appear my RPM is over 200,000. 212,914 to be exact, and it will still make it to 100 yards and group. I think 140,000 or even 130,000 that was suggested over on the cast bullet association is an arbitrary number based on what I am experiencing unless like I said powder coat has something to do with it. Of course I have also not reduced this velocity to see if it could be potentially sub MOA. Frankly, I don't think it would make a difference.
It would be interesting to test this theory between the 300 blackout RPM and velocity, and the 308. With a 1/10 twist I could potentially go up to 2950 FPS and still be in that 212,000 RPM range. Do you think the accuracy I am seeing would hold? I could drop RPM to increase accuracy, but hey under 2" for a battle rifle with cast for me is usable for a couple of hundred yards if not 300.
Off topic a bit, but that's just how I roll....

[45 2.1]

It is not a bad boolit to say the least. I am running it in a 7 twist right now so the rpm is even greater. Sized right even straight wheel weights with no water quenching seems to work. I did not see any appreciable gains from water quenching at this RPM as far as accuracy. Who knows, maybe the powder coat keeps it together better. I would not use it on any game I wanted to eat due to the impact reacting like a varmint grenade. With the small HP, at 60 yards it completely blows, at 120 yards, the grease groove back stays all the way thru. Considering this little number has potential to 300 yards with the light boolit weight, that should be good for any varmints I shoot.... or precise use. I imagine a modification to the NOE to include a small meplat would help with its accuracy issue. The nose bending is something that concerned me in the design for a semi auto, and my concerns were validated. If it had a meplat, and a hollow-point I think it would shoot as good as the MP 311-410, but then we are only talking about changing the nose ogive to a TC at that point. What would be the benefit if any? Percent of bearing surface and alignment features will have more to do with hitting than any nose that doesn't touch anything with the smaller meplats.

It would appear my RPM is over 200,000. 212,914 to be exact, and it will still make it to 100 yards and group. I think 140,000 or even 130,000 that was suggested over on the cast bullet association is an arbitrary number based on what I am experiencing unless like I said powder coat has something to do with it. Of course I have also not reduced this velocity to see if it could be potentially sub MOA. Frankly, I don't think it would make a difference. Don't even consider RPM limits... you get it to fit right and use the correct alloy/hardness with the right load and you can go well over 210,000 RPM....BTDT with the 6x45 with excellent accuracy in an AR.
It would be interesting to test this theory between the 300 blackout RPM and velocity, and the 308. With a 1/10 twist I could potentially go up to 2950 FPS and still be in that 212,000 RPM range. Do you think the accuracy I am seeing would hold? I could drop RPM to increase accuracy, but hey under 2" for a battle rifle with cast for me is usable for a couple of hundred yards if not 300.
Off topic a bit, but that's just how I roll....

For the 308, I'm mostly shooting the 30 Sil in the 2,400 fps area (dependent on just which barrel length I'm shooting at the time) in bolt guns and semi-autos with equal excellent accuracy. The fit and alloy composition with requisite hardness are important here. Light boolits may be another story in the 308.... one I don't intend to pursue at this time.

[GoodAlloy]

xacex ~ what powder and charge are you using with the wheel wieght mix??

I have not thought about the nose bending....Hum... Maybe thats why I had better results with the really hard ones.. Maybe the softer ones were getting beat up on the feed ramps. A single shot fast twist would make a good testing tool to eliminate the nose damage effect on feed ramps. Then perhaps I could ease up on the BRN hardness a little bit & increase the boolit wieght some. All I know is when I went really hard alloy she started grouping really well at the higher velocities.

[xacex]

xacex ~ what powder and charge are you using with the wheel wieght mix??

I have not thought about the nose bending....Hum... Maybe thats why I had better results with the really hard ones.. Maybe the softer ones were getting beat up on the feed ramps. A single shot fast twist would make a good testing tool to eliminate the nose damage effect on feed ramps. Then perhaps I could ease up on the BRN hardness a little bit & increase the boolit wieght some. All I know is when I went really hard alloy she started grouping really well at the higher velocities.

17.7 H110 is the charge on that one. The nitty gritty is in this thread. http://castboolits.gunloads.com/show...-greater/page8

I would make the NOE as hard as you can get it, and size it to .310, or even .311 if your rifle will take them that size. It is a lead boolit so no matter how hard your alloy is it will still not act like a FMJ on game.