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Posted: 7/29/2008 10:20:14 AM EDT
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OK, Search didn't turn up an answer so here goes..... The Sierra manual lists Rem 7 1/2 primers for .223 bolt gun loads. Anyone have any expierence with a substitute, such as CCI 400 or CCI BR? Thanks for your time, OFG |
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Anytime, you don't exactly follow what THE BOOK says.......you take a chance. As you have noticed.........the BOOK specs what brand of: brass, primers, bullets, powder (and charge weight)......not to mention what brand of firearm they used........to test their load data. The BOOK will WARN that changing components is a bad idea. Not to mention, that different BOOKS have a different idea about WHAT IS SAFE and what is an acceptable level of SAFETY. So......IF you have a low tolerance for RISK......perhaps, you're better off going to the store and finding the components to match the BOOK. But, handloading is part experimentation. So......IF you have a little higher tolerance for RISK......perhaps, you could/would "take a calculated RISK" with a switch in components. Standard advice.....when starting a new load......start low and work your way up. NOTE: Bolt gun ammo or load data, isn't always O.K. w/ a semi auto. And, powder burn rates differ. So, IF a manual doesn't happen to have X Powder listed for a certain caliber then, maybe it isn't suitable. So, go look in a different manual or switch your choice of powder. ___________________________________________________ Just making a "minor change" can have an unwanted affect.....maybe even to the point of being DANGEROUS. Read: How do changing various components affect chamber pressure and velocity? www.frfrogspad.com/miscelld.htm#components Aloha, Mark |
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Yeah, driving to work was a risk too. BTW, the Sierra book lists loads for both AR 15s and bolt guns. I know not every .223 round ever loaded used Rem 7 1/2 primers so I'll look a little more and at least get some sort of published other flavor of primer. Good info on changes in pressure due to "minor" changes - thanks. I understand that ANY change in case, primer, seating depth, phase of the moon, etc. really needs to be worked up just like any new load. OFG |
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I long ago standardized on CCI mil-spec primers on any rounds that might concievably be used in any Semi-auto I owned. I use other primers in rounds for my bolt-action rifles, and match rifles, but they are strictly segregated. I won't use them in my semi-autos unless it is a real emergency. YMMV, but my way is safer and gets the job done. |
Raf, this is because the CCI 41 mil-spec primers have the thickest cup with the least chance of slam fires, correct? I have also considered making this switch, I am currently using CCI 450 SRM primers, which I have heard are very close to the CCI 41's in cup thickness. |
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Perhaps, I'm mistaken, or wasn't clear and I apologize for that. IF you change your primer from X Brand to Y Brand. It's BEST to to start low and work your way up. That advice about starting low and working up, is STANDARD, for any NEW load and/or when developing a load. Sometimes a manual will give a range (max and min) of powder charge weight. So, start with the min load, when you switch from Brand X to Brand Y primer. Or, go ahead and reduce some more IF that will make you feel more comfortable. Then, sometimes a manual will only state a max charge weight. So, reduce the charge weight by say 10% (or more IF you want more comfort) to make a starting load. _______________________________________________ Now, since it was mentioned about CCI........... Well, CCI (and some others) will say to use "Military Spec" primers (or Magnum primers because, of the "harder" cups) when loading for a Military Rifle. The RISK is with the possibility of a "slam fire."
So, follow the advice or not..........it's a free country. ________________________________________________ Aloha, Mark |
What CCI says is that their milspec primers are constructed so as to reduce the chance of a slam-fire. Whether the cup metal is thicker, or the anvil/internal construction is different, or both, I don't know. CCI also says the primer composition is such that it will reliably ignite in very low temps, something other primers might not do reliably. The final note is that, slam-fire resistance aside, the primer is functionally the same as a Magnum rifle primer. Again, this is only in terms of flame propagation, and ignores the very different construction between mil-spec primers and civvy primers. The Mil specs these primers for a reason, and the reason is the construction of the M1.iA, AR, Mini-14, and M1 Carbine, namely: a free-floating firing pin. There will be plenty of folks telling you that they have shot zillions of civvy primers through their rifles with no effect. I've done the same, with meticulously prepped, primer-pocket-uniformed Match rounds, each one primed with a sensitive hand-primer device.. That is another story, and one for advanced semi-auto handloaders. No offense. there is no substitute for good reloading practices, and milspec primers do not relieve any handloader from following good practices in reloading. Milspec primers are a form of insurance, NOT a guarantee. That said, it is an insurance I an entirely willing to pay. To address your question directly, the above responses telling you to play it safe and reduce powder charge by 10% are correct. My experience with the ml-spec primers is that you will save enough powder to almost recoup the additional expense that the milspec primers incur. It's a no-brainer for me. YMMV. |
| I agree with Mark that if you change ANYTHING in a load you should work it up all over again. Usually, I'd say that primers wouldn't be a big deal, just crank the load back a couple percent and check it out. With a load that's already pretty hot, I'd crank it back a bit further, but still not more than 5%. A primer CAN have an impact on both pressure and velocity, so be careful. |
Yup, THIS. I had to switch Federal primers out for CCI due to availability and worked the load back up from 90% to 100% again. Worked fine and everyone's happy. Oh yeah, I've been reloading since about JUNE so I tend to err on the side of caution. It's a habit I aim to keep. |
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Thanks for all the information. It looks like going with a different brand, but same type, primer and working up loads from the low end will not be a problem. Good to know as Rem 7 1/2 primers are listed as "out of stock - no backorder" too much of the time. Thanks, OFG |
Try to find the 5% recommendation in a modern load manual. I don't have a copy of everything published, but I've at least flipped through them, and if it's in one, I missed it. I'm pretty comfortable with 5%. That's after I worked from 10% and then 7%. |
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If your loads are not near the top end---I don't load to those pressures anyway---a primer change will not affect the pressure by much. You might find that a CCI primer will give better accuracy, or not in a particular rifle. However, if you are loading toward the top end of safe pressures for your rifle, then a primer change could bring the pressures over the top. If you are one who tries to get the most velocity, then back off the powder charge when making a primer change. If on the other hand you are like me and your "max loads" are ~5-7% from max listed anyway, primers can be changed at will. (I like longer case and barrel life.) |
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REDUCE 5% or 10%........even the manuals will differ on: What's an acceptable level for someone else's SAFETY. I (personally) don't really care what % reduction (5% or 10%) he chooses. As long as he realizes the RISK and does what he is comfortable with. I just wouldn't like to see anyone get hurt. Aloha, Mark PS......now that I think about it.....I'd probably use a 5% reduction IF it's just a subsitution of a primer brand (all else, being the same as the BOOK) and IF, I've used that load data before. However, a 10% reduction is a good (easy to remember and calculate) for a NEW (un-tested in YOUR firearm) load or IF several "minor changes" are made. What's "minor"......I leave that to YOU to figure that one out. |
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