223 AI question

[Pareto]

I recently had my 223 AI bench gun checked out by a smith who changed out the firing pin spring due to some light primer strikes as well as adjusting the Jewell trigger slightly. Now the gun shoots very well and accurately with any of my handloads, but shooting factory 223 ammo -- like bulk Winchester or PMC 55 grain -- I'm getting light primer strikes every third shot. What is the likely culprit? This is an accurized single shot Rem 40X BR.

Thanks for any suggestions.

 

[B23]

That ammo could have the cases slightly undersize, sometimes they do that so the ammo will chamber in everything particularly AR's, and if the ammo/cases are a little short on headspace and loose in your chamber it could be that the firing pin is actually pushing the case forward when the firing pin is striking the primer.

Is this by chance a barrel that was once a 223 then was rechambered to 223AI??

 

[RegionRat]

I would ask the smith why the spring was replaced, was it verified wrong or weak?

Why did the trigger need adjustment, was it just to adjust trigger pull, or was it in relation to firing pin release?

If those issues were done because the smith knew they were needed, then maybe there is still more to do?
If those things were done, but were not verified as wrong beforehand, then you may still have more to do?

If so, then you may want to divide the troubleshoot list between ammo fit and ignition problems.

I will suggest you custom load some fireform loads with jam, false neck, and/or both, and see if the ignition is more reliable with properly headspaced fireforming ammo.

If your custom fireform ammo doesn't headspace correctly, then you know regular 223 ammo is going to be a matter of statistical luck since it will be loose.

If the custom loads are correctly headspaced and you still have ignition problems, then the problem is likely still in the bolt or trigger.

Good Luck and in for the report.

 

[SecondsCount]

I agree with RegionRat. It sounds like a headspace issue

 

[urbanrifleman]

Headspace.

Some factory ammo is really short.

You should have to force the bolt shut on factory ammo.

 

[boltfluter]

I recently had my 223 AI bench gun checked out by a smith who changed out the firing pin spring due to some light primer strikes as well as adjusting the Jewell trigger slightly. Now the gun shoots very well and accurately with any of my handloads, but shooting factory 223 ammo -- like bulk Winchester or PMC 55 grain -- I'm getting light primer strikes every third shot. What is the likely culprit? This is an accurized single shot Rem 40X BR.

Thanks for any suggestions.

You answered your own question. The only issue is with factory loads, which have to fit every chamber of rifle. Excessive headspace is the problem as mentioned several times. Carry on.
Paul

 

[Bill Norris]

^^^^^^^^ What he said.

 

[dmccrerery]

I think it is because you are fire forming 223 to 223AI. I bet reloading spent cases, they will be fine.

 

[Pareto]

I think it is because you are fire forming 223 to 223AI. I bet reloading spent cases, they will be fine.

As I mentioned, all my reloads are fine. Even with new 223 cases, as I seat the bullets close to touch.

 

[dmccrerery]

Look at diagram on accurarta arms. Note the difference in cartridges. the 223 cart. (shorter than 223AI ) will be pushed forward as the firing pin contacts causing a light strike, as it expands to a 223AI. Once the case is fire formed the cast will not expand to form the AI. I'm just an old fool who gives you my opinion and love the 223AIs

223 Rem + 223 AI Cartridge Guide

223 Rem Guide for .223 Remington reloading, 223 Rem accuracy, .223 Rem hunting, 223 AI and 5.56x45 rifles. 223 Remington Brass, 22 bullets, powder, primers and loading dies for .223 Remington. Ballistics drop chart for .223 Rem, .223 Ackley AI, 2-250. 223 Remington Black rifle, service rifle...

www.6mmbr.com

 

[David Milisock]

I recently had my 223 AI bench gun checked out by a smith who changed out the firing pin spring due to some light primer strikes as well as adjusting the Jewell trigger slightly. Now the gun shoots very well and accurately with any of my handloads, but shooting factory 223 ammo -- like bulk Winchester or PMC 55 grain -- I'm getting light primer strikes every third shot. What is the likely culprit? This is an accurized single shot Rem 40X BR.

Thanks for any suggestions.

That's the bitch of wildcat cartridges, (AI versions of standards) shoot the factory rounds that won't work in your bolt gun an a standard 223 chambered rifle.

 

[jepp2]

Even with new 223 cases, as I seat the bullets close to touch.

Close to touch, touch and maybe even hard jam may not be enough. I bought a used 223AI, and although I asked the seller (the gunsmith had passed away), I never could determine if the barrel had been set back or not. I have an assortment of brass with longer case head to datums. None of those would touch. I loaded 20 rounds of the longest, and over half showed incipient case head separations.

Sent the rifle to my gunsmith to set it back a thread. Headspace is supposed to be - 0.004" and it was +0.016". Just 0.020" excess headspace.

 

[Oso]

I had same issue but like a 65% failure to fire rate on a wide selection of factory ammo. I immediately went back to my gunsmith. Chamber was spot on as per Mr. Ackley's design and reamer. However, my firing pin was on short side. Gunsmith immediately replaced factory firing pin spring with a new Wolf spring.

We measured all of the ammo and found it to be as little as .004" short at shoulder datum and as much as .015" short. I bought some new LC brass cases and reloaded in order to get a proper seal for fire-forming 223AI cases in my rifle.

Most ammo manufacturers are making their cartridges short of spec to ensure reliable feeding and extraction in any rifle, especially AR15. It is common practice for gunsmiths to set barrel back by one additional thread to offset the short ammo and ensure proper seal.

 

[wildcatter]

Pretty clear case of to much hrsdspace, and agree, my bet is headspace. How about a picture of this gun. We love eye candy.