AR-10 Primers

fpchief · January 2, 2019, 08:43 PM

Gents,
I am not finding a resounding Yes or No in my searches. I usually reload .223 but an now getting ready to do bulk .308 for an AR-10. I always use the CCI 41 for my .223 (AR's) and need to know if the CCI 200 is ok for the AR-10. I happen to have a few thousand of them and really don't want to go buy some #34's if i don't have to.

Just looking to know if i am safe with the 200's in my AR-10.

Thank you!

**Unclenick** · January 2, 2019, 09:26 PM

The #34's are the same as a CCI 250 except with lower sensitivity due to a larger angle of spread in the anvil feet that gives it the lower military spec sensitivity. The number 200's will be more sensitive and will make a bit less gas (the 250 and 34 are magnum primers). So, will it work? Sure. Is it maximally safe from slamfires like the #34? No. But the AR mechanism, despite its floating firing pin, is generally considered to be less slamfire prone than the Garand and M14 actions the primer sensitivity specs were developed around originally.

I can't tell you what to do nor can I take responsibility for any mishap you might have doing it and neither can The Firing Line board, so I'm not going to advise you to use the #200. However, I will tell you that in my experience using the arguably even more sensitive Federal 210M in a Garand and M1A, I never had a problem. I believe that was due to having checked that firing pin protrusion was within specification and to being meticulous about seating the primer deeply enough. The majority of slamfires come from improperly seated primers.

Primers need to be seated until their anvil feet touch the floor of the primer pocket and then compressed an additional 0.002-0.004" deeper. They should end up about 0.004" below flush with the face of the case head. If you do that, the odds of a slamfire go down. But, that said, we have one board member named Slamfire who has had two Garands blow apart on him due to out-of-battery firing with those same Federal primers I used. So, never say never.

Over a number of years shooting service rifle matches, I can think of all the times I heard slamfires occur on the command to load. I've estimated from that experience that it was about one in 15,000 rounds. I can't guarantee the accuracy of that number, but it seems to be in the ballpark. So if you decide to go ahead with the #200's and you have a lot fewer than that, I just wouldn't buy them for that AR again when they run out. I'm not clear how much advantage the less sensitive primers will give you. I was present for a slamfire with a round of Lake City ball ammunition one time, so I know the less sensitive primer with proper seating isn't an immunity guarantee. It is just likely to improve the odds of avoiding a slamfire or an OOB (Out Of Battery) firing.

fpchief · January 2, 2019, 10:10 PM

Outstanding reply!!! I really appreciate it.

Sent from my SM-G955U using Tapatalk

T. O'Heir · January 3, 2019, 01:57 PM

CCI "Milspec" primers are nothing more than magnum primers. You don't need 'em for your .223 either. Unless you're using a powder than requires 'em. Brilliant marketing plan though.

Rod47 · January 3, 2019, 02:18 PM

Uniforming primer pocket depth would be a good place to start.

**44 AMP** · January 3, 2019, 03:46 PM

Take several rounds loaded with CCI 200s and chamber them in your AR-10, without firing. Let the mechanism chamber them normally. Look at the primers after you extract the unfired rounds.

If there is a tiny mark or no visible mark on the primer from the firing pin, you should be fine. If there is a "dimple" you are borderline for a slam fire. Probably safe, but not certainly so.

I've used CCI 200 in my M1A for decades. There is a small dimple on the primer where the firing pin bounces off it during chambering. To date, I have never had one go off from that, BUT I am aware of the possibility, and act accordingly.

Like Uncle Nick says, the AR system, while also having a floating firing pin, is "softer" than the M1/M14 system when it comes to the firing pin bouncing off the primer during chambering.

For piece of mind, use the milspec primer. Otherwise, I don't think it matter a lot, as long as you hope for the best, but plan for the worst.

berettaprofessor · January 3, 2019, 05:48 PM

I use CCI 200's. No issue.

bobn · January 3, 2019, 07:54 PM

my ar10 armalite, (old manufacture in Illinois) has a firing pin spring.
...oops forgot to add that should help a lot to diminish the risk of slam fires... fwiw bobn

January 2, 2019, 08:43 PM	#1
fpchief Senior Member Join Date: February 12, 2010 Posts: 122	AR-10 Primers Gents, I am not finding a resounding Yes or No in my searches. I usually reload .223 but an now getting ready to do bulk .308 for an AR-10. I always use the CCI 41 for my .223 (AR's) and need to know if the CCI 200 is ok for the AR-10. I happen to have a few thousand of them and really don't want to go buy some #34's if i don't have to. Just looking to know if i am safe with the 200's in my AR-10. Thank you!

January 3, 2019, 01:57 PM	#4
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	CCI "Milspec" primers are nothing more than magnum primers. You don't need 'em for your .223 either. Unless you're using a powder than requires 'em. Brilliant marketing plan though. __________________ Spelling and grammar count!

January 3, 2019, 03:46 PM	#6
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,846	Take several rounds loaded with CCI 200s and chamber them in your AR-10, without firing. Let the mechanism chamber them normally. Look at the primers after you extract the unfired rounds. If there is a tiny mark or no visible mark on the primer from the firing pin, you should be fine. If there is a "dimple" you are borderline for a slam fire. Probably safe, but not certainly so. I've used CCI 200 in my M1A for decades. There is a small dimple on the primer where the firing pin bounces off it during chambering. To date, I have never had one go off from that, BUT I am aware of the possibility, and act accordingly. Like Uncle Nick says, the AR system, while also having a floating firing pin, is "softer" than the M1/M14 system when it comes to the firing pin bouncing off the primer during chambering. For piece of mind, use the milspec primer. Otherwise, I don't think it matter a lot, as long as you hope for the best, but plan for the worst. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

January 3, 2019, 07:54 PM	#8
bobn Senior Member Join Date: December 30, 2006 Location: midwest Posts: 1,105	my ar10 armalite, (old manufacture in Illinois) has a firing pin spring. ...oops forgot to add that should help a lot to diminish the risk of slam fires... fwiw bobn Last edited by bobn; January 3, 2019 at 09:45 PM.

January 2, 2019, 09:26 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	The #34's are the same as a CCI 250 except with lower sensitivity due to a larger angle of spread in the anvil feet that gives it the lower military spec sensitivity. The number 200's will be more sensitive and will make a bit less gas (the 250 and 34 are magnum primers). So, will it work? Sure. Is it maximally safe from slamfires like the #34? No. But the AR mechanism, despite its floating firing pin, is generally considered to be less slamfire prone than the Garand and M14 actions the primer sensitivity specs were developed around originally. I can't tell you what to do nor can I take responsibility for any mishap you might have doing it and neither can The Firing Line board, so I'm not going to advise you to use the #200. However, I will tell you that in my experience using the arguably even more sensitive Federal 210M in a Garand and M1A, I never had a problem. I believe that was due to having checked that firing pin protrusion was within specification and to being meticulous about seating the primer deeply enough. The majority of slamfires come from improperly seated primers. Primers need to be seated until their anvil feet touch the floor of the primer pocket and then compressed an additional 0.002-0.004" deeper. They should end up about 0.004" below flush with the face of the case head. If you do that, the odds of a slamfire go down. But, that said, we have one board member named Slamfire who has had two Garands blow apart on him due to out-of-battery firing with those same Federal primers I used. So, never say never. Over a number of years shooting service rifle matches, I can think of all the times I heard slamfires occur on the command to load. I've estimated from that experience that it was about one in 15,000 rounds. I can't guarantee the accuracy of that number, but it seems to be in the ballpark. So if you decide to go ahead with the #200's and you have a lot fewer than that, I just wouldn't buy them for that AR again when they run out. I'm not clear how much advantage the less sensitive primers will give you. I was present for a slamfire with a round of Lake City ball ammunition one time, so I know the less sensitive primer with proper seating isn't an immunity guarantee. It is just likely to improve the odds of avoiding a slamfire or an OOB (Out Of Battery) firing. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

January 2, 2019, 10:10 PM	#3
fpchief Senior Member Join Date: February 12, 2010 Posts: 122	Outstanding reply!!! I really appreciate it. Sent from my SM-G955U using Tapatalk

January 3, 2019, 02:18 PM	#5
Rod47 Member Join Date: August 3, 2017 Posts: 45	Uniforming primer pocket depth would be a good place to start.

January 3, 2019, 05:48 PM	#7
berettaprofessor Senior Member Join Date: November 23, 2008 Posts: 1,091	I use CCI 200's. No issue.