6.5 Creedmoor Gas Gun Hard on Bullet Tips?

[luvtolean]

I have a Noveske AR-10 upper in 6.5Creedmoor I've been using for tac matches to 1000yds.

I have about 500rounds through it with the only malfunction related to a tight neck holding a round just out of battery past the 100rds since cleaning point. Otherwise, has run great and I've been very happy with it.

I noticed the 140gr Amax bullets, which I loaded to the rec 2.82" COL, were having the tips shaved during feeding, so I decided to try some Nosler Custom Competition 140s to see if I could preserve the bullet tips.

I had to reduce the COL to about 2.74" to keep the new bullet from touching the rifling. I was not crimping, just full length bushing resizing the brass and setting the bullet using a Hornady Match-Grade bushing die.

I took it out to shoot, and had two malfunctions, both times the bullet tip hit the barrel nut, was shoved back 0.10", the case dented and that was it, failure to feed. After the second I just single loaded to shoot.

I'm out here messing around, and I notice that as long as the COL doesn't change, it feeds fine, but shaves the tip of either bullet. If I ride the charge handle forward slow, either the AMAX or the CC hit and stop. I guess the plastic deforming has had enough give to keep the gun running.

Do you guys have these issues with your 6.5Creeds? Any ideas?

 

[Jmilera]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

change mags brother.

 

[JSF]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

I don't have these issues with my 6.5 creedmoor. What mags are you using?

 

[luvtolean]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

I am using Armalite 10rounders. I bought 5 of them direct from Armalite about 6 mos ago.

All work the same and have the same issue.

 

[Jmilera]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

PMAGS

 

[Hellbender]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

The Creedmore case shoulder does not lift the nose of the cartridge high enough (early enough) and the bullet tip hits the flat part of the barrel below the chamfer around the chamber.

DPMS and Armalite both do it, all I've seen in this caliber (and 6mm variants with shorter/steeper shoulders than standard .308/.243) do it to some degree. The Creedmore case design is not optimal for proper feeding.


Mag lips can be opened (front of cartridge lifted) to minimize the problem.

JSF...Get a light and look at the rear of your barrel around the chamber, I bet you will see where the bullet tips are hitting below the chamber.

The bullet tips SHOULD be hitting IN the chamber, with nothing hitting underneath.

Do they work...of course....but anyone care to measure bullet run out after the trip to the chamber?

 

[luvtolean]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

Thanks Hellbender. Can't say I'm happy reading what you're saying, but you're definitely describing what I'm seeing when I watch carefully. I spent time comparing it to a couple of my other ARs with various mags yesterday, and if you compare it to a .223 -15 it's really apparent the cartridge doesn't pop up and aim the bullet direct into the chamber early enough during feeding.

It works pretty well even to 1000yds, but I spend the time at the bench on my ammo, I'd like to tune up the gun as best as I can to keep from undoing my hard work.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hellbender</div><div class="ubbcode-body">Mag lips can be opened (front of cartridge lifted) to minimize the problem.</div></div>

Can you describe exactly what you mean here? I probably have 30 mags for my AR-15s and I've never had to mess with any of them.

 

[Hellbender]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

luvtolean....

I'm really tight on time, I'm leaving to go to the Rifles Only match on Tuesday, but when I get back the week after next, buzz me again and I will take some pics and describe the mod.

 

[luvtolean]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hellbender</div><div class="ubbcode-body">luvtolean....

I'm really tight on time, I'm leaving to go to the Rifles Only match on Tuesday, but when I get back the week after next, buzz me again and I will take some pics and describe the mod. </div></div>

Thanks, shoot well and may the weather match your calls!

 

[majohnson2]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

My 6.8 with PRI mags is also known to damage the tips.

 

[B3dlam]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

Is it doing this with factory ammunition or only handloads?

 

[luvtolean]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

140gr Factory AMAX and reloads both function fine, but mess up the tips.

140gr BTHP Nosler CC has had FTF.

Both are doing the same thing, hitting just below the chamber but the plastic seems to have a bit more give and they reliably make the jump. So far.

 

[sticshooter]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

i'll have to check mine.i've ran factory 140 amax's and 142smk reloads.both shot ok and no malfunctions but i'll have to start checking my tips.ready to hear hell benders solution cause i love this set up.

 

[sticshooter]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

anyone heard from hellbender on the mag mod?

 

[luvtolean]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: johnnyDL</div><div class="ubbcode-body">anyone heard from hellbender on the mag mod? </div></div>

No.

I can say, if I run a .308 shell through it, it feeds perfect.

 

[Hellbender]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

This is NOT a solution, but it may help a little.

By spreading the front of the mag lips a little, you can slightly raise the nose of the cartridge and give it a little straighter shot into the chamber.

This is a DPMS platform with C-Products mags, BTW.

 

[luvtolean]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

Thanks Hellbender.

Been playing with it, to really get it to jump early you have to start the spread back at least halfway down the mag.

The only reason I'm seeing why the .308 jumps better, at least in my rifle, is the fatter bullet holds the tip higher as the bullet rides up the feed ramp.

 

[sticshooter]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

well this kinda sucks.does'nt sound there's much can be done about it.thanks for the info hellbender,i will try it but it sounds like a bad design that can't really be fixed with this combo and max accuracy will be next to impossible to achieve.

 

[pagana]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

Exactly right about the bullet diameter having the effect of raising the round sooner. Had the same problem with my custom .260 and ended up sending it to Accuracy Speaks. In fact, if you have their book it has a blueprint for what the chamber end of the barrel must look like in order for the tips to clear whendropping down in caliber. Basically it entails lathe cutting a cone at a 60 degree angle to a diameter no greater than the main bolt diameter. The explanation for the deficiency in the AR platform can be found in the writings of Tubb when he setup his SR25 for High Power, i.e. the ramps are steep without enough lug height to allow the rounds to rise and straighten before entering the chamber.

 

[sticshooter]

Re: 6.5 Creedmoor Gas Gun Hard on Bullet Tips?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Toolmakr</div><div class="ubbcode-body">Exactly right about the bullet diameter having the effect of raising the round sooner. Had the same problem with my custom .260 and ended up sending it to Accuracy Speaks. In fact, if you have their book it has a blueprint for what the chamber end of the barrel must look like in order for the tips to clear whendropping down in caliber. Basically it entails lathe cutting a cone at a 60 degree angle to a diameter no greater than the main bolt diameter. The explanation for the deficiency in the AR platform can be found in the writings of Tubb when he setup his SR25 for High Power, i.e. the ramps are steep without enough lug height to allow the rounds to rise and straighten before entering the chamber. </div></div>thanks for the info,what did that little mod run you?