Gunsmithing Issue with new AR10 6.5 Creedmore upper

[WolfAr]

Greetings y'all

Yesterday I finally bit the bullet and purchased an AeroPrecision 6.5 Creedmore upper to replace my 7.62/.308. I purchased the upper at a local gunshow. I'm putting this on a Bushmaster lower which I've used for over 8 years and never had an issue with it. Got the new upper home and married it to the bushmaster lower and discovered that I'm not able to manually lock the bolt back. With no magazine in the weapon, pulling the charging handle back as far as it will go, it feels like the bolt is not getting behind the lock. I'm wondering if this is due to my buffer/spring maybe being too strong? Or is there something else I should be looking at? I would appreciate any advise or suggestions.

TIA

Wolf

 

[padom]

What buffer tube, buffer and spring?? If a rifle length buffer, is it a 308 or AR15 rifle length buffer. 308 is shorter. If you use a AR15 rifle buffer bolt wont go back all the way, they are longer than a 308 rifle length buffer

 

[WolfAr]

A2 or M4?

Definitely yard the buffer works out,count coils and KNOW where you are at.

I know it's an A2 rifle buffer tube because I had to switch out the buffer tube when I put on the Magpul PRS Gen2. The buffer tube that was installed was too long. The A2 tube was just right.

 

[padom]

What buffer tube, buffer and spring??

I know it's an A2 rifle buffer tube because I had to switch out the buffer tube when I put on the Magpul PRS Gen2. The buffer tube that was installed was too long. The A2 tube was just right.

What buffer??

 

[WolfAr]

What buffer??

I took a few measurements. The spring is 12 1/4 in length with 36 loops. The buffer itself is 5 1/4 in length. I don't have a scale to weigh the buffer on but it feels pretty hefty and, from the pictures I've seen, it's a .308 rifle buffer. I'm wondering if a shorter buffer would fix my issue.

Thanks, again
Wolf