View Full Version : CCI #41 and TAC
Worked up a 5.56 load over the summer, all I had was CCI 400 primers.
Now all I have left are CCI #41 primers.
Per Justin at ATK the #41 primers are magnum and the 400 are standard and are not interchangeable.
Does anyone have a 5.56 load they have worked up using TAC and #41 primers ? I'd like to work one up but it's -17 degrees here right now
and have no plans to go out until it's at least 20 degrees. Just looking for a starting load and a possibly a max load.
I stopped at 26.6 for a max load in the summer with CCI 400 primers and settled on 26.3 as the sweet spot for velocity and accuracy.
Given the current shortage of components, sending another 500 rounds down range to get a "perfect" load isn't an option. Hitting an 8" pie plate
at 100 yards will do as long as primers don't flatten or crater too much.
Upper is a 1:7 BCM BFH
Brass is 1x LC
Powder is TAC
Primers are CCI #41
Projectiles are 62 gr SS109
I'd like to start safe, that is a given. Just not sure starting at 10% under my max load of 26.6 is a viable option given the projectiles I have left to load are limited with no set time frame that stock will be replenished.
Ramshot lists 2 max loads, one for SAAMI and one for Nato/ Military. You're over the Nato already. They have 25.9 as max.
Go to their website and you can download a copy of their loads.
Not saying yours is way way over, I've had max loads over published stuff too.
I've been using 24.5 grains of TAC with CCI 41s and Wolf SRMs and SS109 bullets. I don't have any chrono data but based on the grouping I get at 50 yards, an 8" plate at 100 should be a cakewalk.
I already have the Ramshot NATO load data and worked up that load for quite a while using that data.
Barnes NATO load is 27gr of TAC with the 62 gr TSX so who's wrong ? Neither one I'd say.
Just wondering what experience has been with the #41 primers running 5.56 loads with TAC.
What kind of changes will the current cold temps impose on loads ?
I developed the last set during the hottest time of the year here ( 85 + ) and now the temps are in the low teens and under.
RearwardAssist
01-26-13, 00:01
What kind of changes will the current cold temps impose on loads ?
I developed the last set during the hottest time of the year here ( 85 + ) and now the temps are in the low teens and under.
Hotter temps increase pressure (increase burn rate)typically, although some powders are resistant to temperature swings. So the danger is working up a max load during the winter and then shooting it during the summer. Tac is considered to be pretty temperature stable though.
Hotter temps increase pressure (increase burn rate)typically, although some powders are resistant to temperature swings. So the danger is working up a max load during the winter and then shooting it during the summer. Tac is considered to be pretty temperature stable though.
That is the way I understand the temp differences as well. Guess a max load is out of the picture for the winter.
I'll have to test what's loaded so far but am thinking the current temps may result in a non issue. The only sure bet is what happens in reality and what happens on paper will be different.
Starting at 10 % under doesn't make much sense even with #41 primers since that is at minimum for the 5.56 data from ramshot with WSR primers...but I can test none the less. 5% under seems more realistic and skipping a max load until summer time would be in order.
*****
Helpful...
These are not intended to be used for punching holes in paper.
What are other loaders goals here when loading to 5.56 pressures ?
I accident erased what i wrote on my phone and did not feel like typing it again.
Understood.
Not much out there yet on use of TAC & #41 primers.
Emailed the guys that make QuickLoad to see if at least TAC is included in the database. Not sure if they offer primer as an option or not. Would have to be a magnum primer but very few results so far with magnum primers like the #41 and TAC in the same data set.
2nd email off to CCI...
Take your known good load that you have worked up before drop it by one grain. Load 3 rounds from the lower weight to your normal load.
So if your normal load is 24.0. Load 23.0, 23.5, 24.0 if you do not have excessive pressure at your old load shoot a couple groups. If it performs up to your standards you know your old load is fine.
When switching primer i generally use that method. Generally the load will perform equal to the old load. Primer do not vary that much even from standard to magnum. You may need to add or drop the load by a couple tenths, but there should not be that much difference. Especially from 400 to 41's.
41's will actually handle pressure better due to the thicker cups. The biggest difference is the cups. They are not much hotter even though they are considered magnum.
Back in 2002 I did some very limited testing with magnum, standard, and bench rest primers using TAC powder. What I found was the primer had almost no effect of velocity. This is with TAC, something like BLC 2 is a different story.
Thank you both for the insight. jstone, your method is very similar to what I had in mind. While I doubt there would be much difference in velocity, as mentioned by 5pins, I'm more concerned with chamber pressure at this point.
Working back up the velocity will be in order, I just wanted an idea of what the #41 are going to do to chamber pressure.
Virtually nothing. The reason for dropping a grain is that a difference in primer at most will roughly equate to 1 grain in powder. The 41 handles pressure better as well. I do not know your load and how it performs in your rifle, but a safe load that is not causing excessive pressure is not going to wildly spike with a different primer.
Your load is up there, but if it has not caused problems while using 400's you Will be fine with 41's. That is what the small work up is for so you are sure of pressure as sure ad you can be without pressure testing equipment.
With your load you should be more worried about when you change lot #'s of powder. Different lots of powder can cause more problems then a change in primer.
Not to necro my own post but finally got a chance to get out and test the old loads. Granted it wasn't 70+ degrees but there were no issues with primer flow, blown primers or case issues.
You can tell they are pretty hot loads even with a suppressor but no issues were seen in the gun, cases or primers. I still plan on bumping the load back down but will wait for actual hot temps for that. Just wanted to pass along the info in case anyone else ran into the same situation.
Not apples to apples here.... but the only time I've done a Magnum to Non Magnum primer test was with .308. Subbing Large Rifle Magnum primers actually lowered velocity about 50 FPS if I remember correctly. (this was with Varget)
Not apples to apples here.... but the only time I've done a Magnum to Non Magnum primer test was with .308. Subbing Large Rifle Magnum primers actually lowered velocity about 50 FPS if I remember correctly. (this was with Varget)
I have found the same thing with small rifle magnum primers and Varget.
I have found the same thing with small rifle magnum primers and Varget.
Nice target powders seem to like a mellower primer. I've seen this with H322 as well. Someone here was running #41s with H322 and getting short strokes on a rifle gas system... problem fixed with mellow Russian primers.
Nice target powders seem to like a mellower primer. I've seen this with H322 as well. Someone here was running #41s with H322 and getting short strokes on a rifle gas system... problem fixed with mellow Russian primers.
Thanks for sharing that, I'll have to write that little tidbit down in the reloading notes.
was working up a max 556/77gr load with tac at 24.5 with cci 41 was getting case head smears by the ejector, switched to WSR and problem went away. but I still use 41's for my 55gr loads of 24.5 of tac or 2230 great function and it feels like i'm shooting a high dollar air rifle winter or summer
Alaska3006
05-11-14, 11:35
Yes I load TAC @ 24.2 with CCI 41 in LC brass with 77 MK @ 2.245" COAL in a MK 12........very good load.
Closely duplicates MK 262 Mod 1 load.
Just looked up Ramshots 5.56 data in version 5 of their guide and it looks like they bumped up the max load for the 65 SIERRA SBT, which was the weight I used to work up the original load. Not too far off where I ended up.
Alaska3006
05-12-14, 22:49
CCI 41 are a Mag Small rifle primer......so Ramshot TAC data will be to Hot with Mag primers.
I believe the last MK 262 Mod 1 was with WC Brass and WSR primers....and TAC
I have chronoed Hornady 55gr in LC brass with 25gr H335, 23.5gr H322 and 26gr TAC and several different primers.
Primers included Original Winchester SM rifle (silver), CCI #41, Rem 7 1/2, Wolf SM Rifle Mag. With all powders the CCI #41 produced about 50-70fps higher velocity than the others.. Except for SD and ES the other primers were very close in performance. Based only on these tests and conditions I concluded that using a CCI #41 was equivalent to about .5gr of powder. None of the loads produced any pressure signs in a 16" middy with a measured NATO chamber. Primers were flat but not extruded into the firing pin hole and there were no ejector marks on the cases.
With all powders the CCI #41 produced about 50-70fps higher velocity than the others.
That's pretty interesting.
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