Magnum primer quandry


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nobody_special
July 25, 2007, 03:27 AM
More newbie questions...

I purchased a bunch of CCI 34 primers, since they're specifically made to reduce the chance of slam-fire in an autoloader. I'll be loading for my M1A. Also, as recommended, I got a jug of IMR 4895. I haven't purchased bullets yet. (Or the press, but that's just a matter of time and when it'll be in stock at a good price.)

For .308 using IMR4895, the Speer #13 manual shows a loading of 41.0 gr. (start) to 45.0 gr. (maximum)... but that isn't with a magnum primer. I read that one should reduce the load by 10% when using a magnum primer.

Here's the problem: the permissible range of powder weight only has 10% variation. If I were to work up a load from the 41.0 gr. minimum, and the magnum primer is equivalent to a ~10% increase in powder, then I'd be starting near maximum pressure. But they also warn not to go below the minimum pressure. What to do?


I have another question: is it tricky to substitute surplus pulled 30-06 M2 ball bullets when loading .308 cartridges? I know there could be a concern with case volume, but the bullet weights are similar. I don't know if the lengths are similar, or how much of an error in OAL might be permissible when working up a load.

I could pull a bullet from my Indian ('74-'75 OFV) "M80 ball" (which may or may not really be M80, as I think it was advertised as having a 150 gr. bullet while M80 should be 146 gr) and calculate how far back the bullet sits in the case, but that still doesn't account for variation in powder type and weight.

As an interesting (but short ranged) alternative, I can get cheap .30 carbine surplus bullets, and the Speer manual has loading data for them (though with Speer .30 carbine bullets, and it's probably not safe to assume they are identical to surplus).

I was also going to get some Hornady A-max 168gr. bullets for longer range or more precise shooting, but maybe I'll hold off since the Speer manual only has data for Speer bullets. :banghead: Do I have to get a different manual for every manufacturer's bullets?

The Speer manual has a section (pg. 78) about seating bullets just behind the rifling. I found that odd, as I thought the OAL needed to be fixed in order to get the proper peak pressure.

Can someone shed some light on my confusion?

Thanks...

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jacobhh
July 25, 2007, 09:41 AM
First if you read the primers refernce and comment on pg. 278 of the
#13 Speer manual, it appears to me that the load data assumes you will
be using CCI #34 primers. I don't know why you would want to pull apart
surplus military ammo to get bullets, but I don't see why you can't treat
them as you would any other jacketed bullet of equivalent weight. I always
understood that getting as close to the rifling as possible while balancing
feed and volume concerns is the trick. too short an OAL, I believe,
is the safety concern, but don't take my or any individual's word alone,
check it out in the literature.
I have several reloading manuals. It's a good way to balance your thinking.
Most bullet and powder manufacturers make their data available on-line
and/or in free data sheets. Check the Manufacturer's site.
Richard Lee's Modern Reloading 2nd Edition is a good source. You
get more general information and a large range of powders and he doesn't
sell bullets or powder.
I'm curious as to why you chose IMR4895. I believe its a good choice
because it fills the case but the Speer manual doesn't seem to stress
that.

jacobhh
July 25, 2007, 09:57 AM
Sorry that somehoh posted twice, my bad.

USSR
July 25, 2007, 12:19 PM
nobody_special,

I load alot of IMR4895 in both .308 and .30-06, but it's kind of hard to give you advice without knowing what weight bullet and what brand brass you will be using. M80 bullets will vary from 144gr to 147gr, depending upon country/manufacturer. Loads with LC brass use alot less powder than loads developed with Winchester brass. Need more info, but in any case, using a reloading manual "minimum load" with your #34 primer will not get you in trouble if you are using the same brass that was used in the reloading manual.

Don

Sunray
July 25, 2007, 01:02 PM
"...What to do?..." Follow your manual religiously and you'll have no problems. Only use magnum primers when your manual says to. Magnum primers burn a bit hotter for a bit longer than regular primers. They're made to light hard to ignite powders and for when the outside temperature is low in winter. Otherwise you don't need them. Go buy a copy of The ABC's of Reloading too.
"...reduce the load by 10% when using..." Reduce the charge by 10% when using milsurp brass. It's a bit thicker than commercial so it has a slightly lower case capacity.
"...they're specifically made to..." They're specifically made to separate you from your money. You don't need them to reload anything. Nor do you need magnum primers. Regular large rifle primers work just fine when seated properly. Lots of .30-06 and .308 was safely loaded for semi-auto battle rifles long before CCI #34's came along. Not that the M1A is a battle rifle. It's not. It's a commercial copy of one.
"...substitute surplus pulled..." Load for the bullet weight, not where they came from. M2 ball uses a 150 grain bullet. 7.62NATO uses a 147 grain bullet. That's close enough. You won't get great accuracy using milsurp bullets though. They weren't made for that. You will get decent plinking ammo though. For top notch accuracy out of your M1A, use 168 grain match bullets, regular large rifle primers and IMR4064 for distances up to 600 yards. 165 grain hunting bullets with the same powder and primer. 175 grain Matchkings with the same powder and primer for distances past 600 yards. IMR4064 gives more consistent accuracy than IMR4895. Especially with match grade bullets like the A-Max. IMR4895 will do though.
"...get a different manual..." Nope. Get a Lyman manual. It has more loads for more powders and bullet weights than any bullet maker's manual. Again, load for the bullet weight, not who made it.
"...seating bullets just behind the rifling..." Generally speaking, optimum accuracy comes with bullets that are seated just off the lands. However, every rifle is different. Some will like the bullets just off the lands, some won't. The worst part of it is that finding the optimim OAL is a trial and error thing. It's one of the things you do to fine tune a load. Don't worry too much about it until you find a load your rifle likes. Then you can try different OAL's.
"...can get cheap .30 carbine surplus bullets..." The .30 Carbine uses 110 grain FMJ bullets of the same diameter as the .308/7.62. They'll work, but they're not ideal for your M1A. Some shooters will work up a load using them for shooting varmints though. Speer 110 grain 'Plinkers', either the HP's or SP's, work extremely well out of an M1 Carbine. For a new guy, you'd best deal with one load at a time.
"...Or the press..." Have a look at the RCBS Beginner's Kit. Gives you everything you need to get started less dies and shell holder.

Mark whiz
July 25, 2007, 01:35 PM
First off, the pulled bullets will work just fine, just load them to the same spec as you would any other 150gr (144 to 147gr) jacketed bullet. You can expect about 2MOA from mil-spec bullets - they just aren't as accurate as more match-oriented bullets.

I've loaded bunches of ammo for my M1A and I can assure you that that the CCI #34s really are not required to stop slam fires. Slam fires will result for 2 reasons: 1. The primers not being seated deep enough in the primer pocket or 2. the headspace on the case being set too short, causing the round to sit too far back and not allowing the bolt to slide forward into battery, setting off the primer. SO as long as your primers are seated below the case head and your headspace is right on your sized cases - you can shoot any primer you would like.

I've heard that the #34s are magnum type primers, but don't recall if I ever got that verified or not. If they are, magnums are really only suggested for ball type powders anyway - so for 4895 any standard large rifle primer will do. I've tried the #34s and Win LR magnums with ball powders like Win 748 and Hod BL-(C)2 and can say I saw no noticeable difference in accuracy or pressure.

For loading data, just about every powder manufacturer has on-line loading data to use. Specific data for a specific brand/style of bullet is not really necessary, except for maybe the Barnes solid copper bullets. Just match up the bullet weight and style (hollow point match, spire point, blunt nose, etc) and work up your load to those recommendations.

For shooting in the M1A, do NOT try to load your rounds to seat them up near the rifling lands in the barrel. First and foremost on a semi-auto, the round must be sized to feed correctly everytime. If the bullet is too long for the lands, it can either jam during the ejection/loading process of the bolt or even start the slam fire thing going. Just load them to a safe mil-spec of 2.80" and make on very slight changes from that if you want to experiment once you've got a load you're happy with.

Bad Flynch
July 25, 2007, 01:49 PM
If you will check around, do so because the mentioned primers are not considered magnum; they only have stiffer cups. As far as I am aware, the special primers have the same pellet as any CCI 200 or BR-2 primer.

Years ago, the NRA did some real life experimenting with changing bullets. Changing bullets can make a safe load unsafe and by a wide margin, so do reduce the 10% and work up. There are many reasons for that procedure.

The range of permissible loads with 4895 is very broad. The range quoted in data for an M1-A will be for loads that will function the action. You may safely load lower than that. There are many, many reduced loads using 4895 with both jacketed and cast bullets. However, do not load so low that you stick a bullet--you will regret that, I assure you.

nobody_special
July 25, 2007, 02:43 PM
First if you read the primers refernce and comment on pg. 278 of the
#13 Speer manual, it appears to me that the load data assumes you will
be using CCI #34 primers.

Jacobh, that comment indicates that CCI 34 primers are the equivalent of 250 (magnum) primers; however, the load data for 150 gr. bullets on pg. 281 does not call for a magnum primer with IMR4895.

I don't know why you would want to pull apart
surplus military ammo to get bullets, but I don't see why you can't treat
them as you would any other jacketed bullet of equivalent weight.


I won't be pulling apart surplus ammo for bullets. De-milled M2 ball bullets are inexpensive compared to commercial bullets, and they should do fine for practice ammo. I'm also going to get a few 168 gr. match bullets, but this isn't a match rifle.


I'm curious as to why you chose IMR4895. I believe its a good choice
because it fills the case but the Speer manual doesn't seem to stress
that.

That's exactly why I chose IMR4895; that, and the fact that it was designed for this type of ammo, and it was recommended to me by several people.


USSR: For bullets, I'm looking at substituting de-milled 150 gr. M2 ball bullets for the 150 gr. Speer bullets listed in my manual (which, incidentally, gives load data for IMI cases, not commercial cases). The vast majority of my cases are from 70's OFV, though I have some LC, R-P, IMI, and Winchester... but for now, I plan to reload the OFV cases.

I don't know the OFV case capacity, but the case weights are actually greater than LC by a couple grains. I presume this indicates that they have similar capacity to military cases.

Bad Flynch, my loading manual specifically states that CCI 34 are equivalent to 250 magnum primers.

USSR
July 25, 2007, 03:21 PM
USSR: For bullets, I'm looking at substituting de-milled 150 gr. M2 ball bullets for the 150 gr. Speer bullets listed in my manual (which, incidentally, gives load data for IMI cases, not commercial cases). The vast majority of my cases are from 70's OFV, though I have some LC, R-P, IMI, and Winchester... but for now, I plan to reload the OFV cases.

I don't know the OFV case capacity, but the case weights are actually greater than LC by a couple grains. I presume this indicates that they have similar capacity to military cases.

With the OFV cases and the M2 pulls, I would start at 41.0gr of IMR4895 and work up towards 42.0gr or slightly more, while looking for high pressure signs on your brass. 41.5gr of IMR4895 in LC brass with a 168gr bullet is a standard M1A load, just to give you some perspective.

Don

Bad Flynch
July 25, 2007, 04:40 PM
>Bad Flynch, my loading manual specifically states that CCI 34 are equivalent to 250 magnum primers.<

Well, I guess one learns something every day. The small primer is magnum because the .223 series takes a magnum primer anyway--not that it needed magnum fire, but the cups will burn through regular primers.

I had assumed that since the large primer would be used with calibers that do not ordinarily call for magnum primers, they would be standard. However, the CCI website does not make that distinction. I would think that a magnum primer would be detrimental to accuracy in some instances.

Apparently some of these primers are available in two versions, too: a NATO-spec version and a MILSPEC version. That should simplify matters greatly.

jacobhh
July 26, 2007, 04:36 AM
'Jacobh, that comment indicates that CCI 34 primers are the equivalent of 250 (magnum) primers; however, the load data for 150 gr. bullets on pg. 281 does not call for a magnum primer with IMR4895."

The comment goes on to say "They are reccommended for military
style semi-automatic rifles." as well.

If you interpret this to mean that you can't use CCI #34 primers unless
the Speer load data specifically calls for magnum primers. Which is a
reasonable (if not entirely clear) interpretation, Then you can't confidently
use Speer's load data for IMR4895 unless you:

#1 Drop 10% below their published minimum to start (not good), May
be dangerous and probably won't feed.

#2 Forget CCI #34 primers

#3 Forget IMR4895 powder

#4 Use some other load data source. I've looked at five and none
except Speer recommends CCI#34's or magnum primers for
a .308 load, but there may be one out there. Lyman?

#5 Blow off the data books and continue to listen to whomever is
recommending powder/primer combos as you have mentioned.

#6 Follow the exact (verified) Mil Spec recipe: brass, bullet, powder
and COL. and slowly deviate checking carefully.

#7 Contact Speer and ask for clarification and/or additional info (I'd
probably go this way).

It is a quandry. The books are all over the place. IMR claims a max
load of 47.5 grains with 4895, while Hornady recommends a 42.7 gr.
max. The concensus seems to be a Federal 210 or 210Match primer.
The IMR max is with a Nosler bullet specified. Bullet bearing surface
is a factor also which as you were concerned means getting into
specific bullet selection and COL not just any 150 gr. jacketed. The
test data is collected most often using a Model70 Win. which further
muddies the water.

Peter M. Eick
July 28, 2007, 11:27 AM
I shoot c-34's, and 168 seirra's with 4895. My standard load is 39.5 grn of imr-4895 with c-34's and 168 bthp's. 39.5 is mild and you can go up a bit to say 40.5 but I found the sweet spot for my M1A SuperMatch is 39.5 grns. This is with federal gold medal brass.

I suggest you do like I did. Back down 10% (actually I started at 20% because I was paranoid and this would not run the action) and work up till the action runs smoothly and reliably. Once the action was working well, then I chrono-ed and was happy. Finally I tweaked the charge weight back and forth then adjusted the seating and my trimming of the brass. In the mean time I got to be a reasonable shot with it.

So results time. 50 shots, off the bench, load as listed above.

http://pages.sbcglobal.net/eickpm/sm_targets2.jpg

nobody_special
July 29, 2007, 12:42 AM
Very nice! Thanks Peter.

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