Large Rifle Primer
 

A few of the shooters on the now 'defunct' forum, seemed to think that rifle primers are better than shotgun primers. They wrote that the rifle primers burn cleaner, and are more consistent. Since it has been like monsoon season around here, i allowed myself to try and utilize the small rifle primer. This gave me something to do out of the weather, and wasn't like doing chores. All my endeavors to use the small rifle primer, failed to ignite BH209 reliably. Everything i did resulted in hang fire, and no fire. I used the VariFlame, and the 25acp case, which were failures. I finally ended up with the powder right at the base of the primer; this failed, and also showed lots of blow by and pressure.

Had the monsoons ended, i would have quit trying to make rifle primers ignite BH209. Shotgun primers work just fine for me. The past 2 days saw us receive about 1/4 of our average annual moisture. Thus work on utilizing rifle primer continued, but with a change to large rifle primers.

Mountainam suggested modifying 223 brass to utilize large rifle primer. This is what i did.



Then to carry the 223 brass i made a breech plug with a big hole on both ends. The hex head for the wrench was made 13mm, because this is the largest socket that will fit into the barrel.











This morning i headed for the hills to give this work a try. The load was 270g Deep Curl in a Harvester sabot, pushed by 115g BH209, ignited by CCI large rifle magnum primer in the modified 223 brass. One of the primers didn't ignite; i think it was because of contamination by cutting oil. The second shot is the one that left the target, and went low. I am thinking that is probably my fault, but i didn't call it. Range was 201 yard.













No flame channel carbon to deal with, um, no flame channel.

Thats excellent 200yd Drivers Seat Window Rest Shooting! :D

I am glad you finally made it work.

The mod looks promising and the fired cases look good. I don't see any primer flow either which is common on hot loads with 209s in many guns. It kind of makes me wonder when i see primers that look like they are on the verge of failure, so its a pet peeve of mine from reloading.

Steel 223/5.56 cases are usually discarded and might work well also. The are usually Berdan primed but removal shouldn't be that big of an issue if you are modding the primer pocket anyway. They may or may not offer an advantage once modified but its a thought.

Another thought.
Is there enough case length left to make them a tad shorter and add a bit more steel to the plug.....maybe 1/4". The powder shouldn't be much further away but "flash channel/case volume" should be reduced but also add a bit more "meat" to the plug above the vent. It could probably be tested with a single thicker white nylon washer in the case pocket for a couple of shots just to test the theory.

Just out of curiosity, can you fill the powder pocket with BH209 and weigh the amount it takes to fill it or get a rough volumetric equivalent. And is that the standard Savage type OD vent or a smaller OD one you made?

BTW nice shooting too. :D

The case can easily be made shorter. However if one is going to be able to use a case trimmer to establish the finish length of the case, it cannot. Reason; the added length of the case is necessary to accommodate the pilot of the case trimmer. These brass i finished to length by using the lathe. I kinda had hoped that i could do this in the future by using a standard case trimmer.

The powder pocket holds about 5 1/2 g volume of BH209. The vent liner head, has been turned down to 5/16" from the standard 3/8". I started doing this last winter, when i noticed instantaneous ignition in sub-zero temperatures whilst using a modified QRBP, that had a 5/16" vent liner installed. This i did because i was trying to understand why just adding a powder pocket to a bad breech plug makes it good to work with BH209.

The primers in them 223 brass show zero sign of pressure. Totally unlike what this STS shotgun primer shows with the exact same load.



The shotgun primer shows quite a lot of flow into the space in the bushing around the firing pin, and the slot in the bushing for a screwdriver. It could be the huge 'flame channel' makes this happen, or is it the fact that the 223 case is what establishes the head space when in use, not the rifle primer. When the shotgun primer is used for ignition, the primer itself is what establishes the head space.

Ron - that is a real interesting endeavor you started there. Nice job.You better get a patent on that idea before someone grab it up. Also, have you tried keeping the primer pocket as a small rifle and using small rifle magnum primers?

No, but it can be done easy enough. Perhaps tomorrow. I don't think small rifle magnums will work though.

Good work and write up as usual Ron....... .Ray

very interesting.. and nice shooting

Tried small rifle magnum primers 3 shots this morning. All were hang fire.

Accuracy was pretty good though. Range was 199 yard. The 3 holes in the top bull were made by 260g Harvester PT bullet in a short black Harvester sabot, pushed by 120g BH209, ignited by CCI small rifle magnum primer.

Hey Ron,

I just found my way over here since MML is down.

Good looking cases and plug. That is the same primer is use in the Speer 38 plastic cases for the MK95. The CCI mag primers were the recommended primer for MK95 by Knight. I never really had good luck with the small rifle primers use 38 spl cases, either. I don't think they have quite the heat and flame needed.

Shawnt

ShawnT

Am inclined to agree that small rifle primer are not enough to ignite BH. Also have discovered that the CCI large rifle primer are made of 'hard' stuff. In my initial test of this plug and brass and primer, one primer failed to fire. In some ensuing tests, a few of the primer failed to fire. There was never a hang fire, but there were a few instances where the CCI magnum large rifle primer didn't pop, and thus there was no fire. I rotated them unfired primer, and mostly they then fired. It seemed to me, my rifle was at fault, and i attempted to correct the problem to no avail.

For some reason it occurred to me to try Federal magnum large rifle primer, and never had another failure to fire. It seems the material of the Federal large rifle magnum primer is softer than the material of the CCI primer. The firing pin of the rifle made a substantially deeper crater in the Federal primer, than in the CCI primer, and the Federal primer always popped, and provided a nice hot spark that never failed to ignite the BH209.

I have also concluded that i never should have given away the hammer extension of the rifle. In retrospect it appears that when one has a rebounding hammer, the mass of the extension is helpful in hitting the primer hard enough to ignite it, because of the rebounding spring.

Another thing, when i decided to switch primer brands, i popped about 10 primed cases. I did this so i could install new Federal primer instead of the CCI primer. When i did this discharging of the primers without powder, the flash hole became completely plugged by the carbon from them CCI primer. I couldn't clear the flash hole with a torch tip cleaner. I couldn't clear the flash hole with a # 70 drill spun by hand. The vent liner, i soaked in solvent for quite some time, and still had a difficult time using the #70 drill to clear the flash hole of carbon. It was my understanding that the rifle primers would be cleaner than the shotgun primers, but that didn't seem to be the case.

Thus far i have seen little advantage to using a large rifle primer, instead of a shotgun primer. The shotgun primer has been very reliable in my rifles, and has caused me no issues. It seems to me, rifle primers require being very fussy when setting up the rifle, breech plug, and brass. The brand of primer also seems some critical.

One lucky group was made by the first three shots of the morning one day, using the CCI large rifle magnum primer. The second primer wouldn't fire, until it was hit 3 times, but when it popped it ignited the BH right now. I have been unable to repeat this accuracy, thus far.

The middle target is 3 shots at 199 yard.

Ron,

This has also been something I have believed, based on what I have seen in centerfire reloading. I have always been a Federal primer user but on occassion CCI was all I could get. and I have noticed that the Federal will flow into the firing pin hole when the CCI would not with hotter loads. I also had a rifle once that had a seemingly light firing pin spring and it gave the same light stikes on CCI but fired consistantly with Fed. I do have one Ruger 77 that I only use the CCI because of the size of the firing pin hole in the bolt.

The MK 95 is really a rebuilt/modified MK 85. The basic action is the same as far as I can tell, except for the addition of the slot for the small bolt handle for the posifire bolt. The Posifire kit is not a one peice bolt such as in the Disc based rifles. It is actually 2 peices, a bolt with firing pin and a plunger striker. I would imagine the plunger coil spring is quite a but heavier than the one in your rebounding hammer rifle. I know it is when compared to my KRB7. I would also tend to believe you are right about the hammer spur too. It would tend to add some weight which would add to the forward moving mass of the hammer. With the KRB, they had a few hammer safteys that would rock back into "Safe" when fired due to the added weight of the hammer spur.

I have seen some slight blockage of the flash hole in my plugs using the CCI mag primer, but it was not near as hard as what you described, but then again I do not recall popping of 10 in a row either. In the cases I saw it was more like ash and was easily removed. I have also used the Federal and Remington Mags as well with good results.

While it is a great experiment I would tend to agree that it is a lot of work you are doing for no so much in return. But I do envy you having the equipment to do this. Hats off to you. :hail:

ShawnT

Equipment and rainy days. One doesn't need a lot of room either. Hobby lathe and mill are not so very heavy and large. I believe you once mentioned a lathe; perhaps it is time. Remember, tooling will cost as much as the machine.

Ron,

I would love to have a lathe and mill, even the small hobby type would work for some of the things I would love to work on. But I live in an apartment, so no way that will happen anytime soon. Largest thing I have is a small benchtop drill press. Someday though.