Max projectile length for AR15 magazine?

[3MTA3]

so then that means the donut problem is not related to how far into the case the bullet protrudes....?

No, seating depth is completely related. It seems that when a bullet protrudes case pressure when fired forces brass from the shoulder to the neck thickening it. This causes narrowing at the case neck junction - the donut itself. Perhaps that's part of the reason for newer case designs having steeper shoulders. I'll have to read through my electronic copy of PO Ackley's book to see if that factored into his design process.

 

[Koda]

No, seating depth is completely related. It seems that when a bullet protrudes case pressure when fired forces brass from the shoulder to the neck thickening it. This causes narrowing at the case neck junction - the donut itself. Perhaps that's part of the reason for newer case designs having steeper shoulders. I'll have to read through my electronic copy of PO Ackley's book to see if that factored into his design process.

so it sounds like there is a limit on how far into a case a longer projectile should protrude.
A good metric Im guessing is the base of the bullet should be close to the neck shoulder?

Leave it to me, especially as a beginner... to find the most obscure difficult problems to work out learning to reload. I just simply thought it would be fun to develop a handload for the AR, something more capable for game to bring when scouting. At least I knew to ask.

Im content with using shorter, lighter bullets, this isnt a high priority for me. What sucks is I wanted to also consider using a 62gr Barnes TTSX bullet but they no longer list bullet length on their website... swear they used to. I think the 64gr Hammers will work though and that should be a good handload.

 

[Koda]

ASC STAINLESS 233 mags will allow up to 2.316 nominal. Remember STAINLESS. They will let you have a great deal more flexibility and get you closer to the lands that us often a help in accuracy. They are also relatively inexpensive compared to the PRI. They make them in other flavors too and are a godsend on my 6.8 and 6.5 wildcats.

Greg

Thanks for sharing this. I ordered two since they were less than half the cost of the PRI mag. I was skeptical of the low cost but if they dont work out then I'll get the PMI mag mentioned above.

 

[3MTA3]

so it sounds like there is a limit on how far into a case a longer projectile should protrude.
A good metric Im guessing is the base of the bullet should be close to the neck shoulder?

Leave it to me, especially as a beginner... to find the most obscure difficult problems to work out learning to reload. I just simply thought it would be fun to develop a handload for the AR, something more capable for game to bring when scouting. At least I knew to ask.

Im content with using shorter, lighter bullets, this isnt a high priority for me. What sucks is I wanted to also consider using a 62gr Barnes TTSX bullet but they no longer list bullet length on their website... swear they used to. I think the 64gr Hammers will work though and that should be a good handload.

It sounds like any protrusion beyond the neck can/will lead to this. I don't know if more protrusion causes more of the effect.

 

[DizzyJ]

The donut is not a problem if the bullet doesn't sit too far back into the neck.

I don't know if bullet seating depth has anything to do with the formation of said donut.

IIRC it's due to brass movement on brass with shoulders. I'd have to go back and read to verify.

 

[DizzyJ]

Here's some answers to your questions. Took me awhile to dig through the books and find them, but here you are.

 

[DizzyJ]

I'd highly recommend these books to anyone wanting to learn how to squeeze more accuracy and consistency out of your loads.

 

[Koda]

@DizzyJ thank you for taking the time, incredibly valuable information a beginner like me would be near impossible to find. I'm glad I asked this question, I can now find a suitable projectile length for my project that will be optimal for the rifle magazine I use. I am very grateful for the attention youve made to my reloading posts and questions including offline conversations.