Bullet Seats into Powder?

[Thumb]

OK, I'm loading up some .223 rounds and am trying out some Sierra 80gr HPBT bullets using Varget 23.4gr. Problem is and maybe it's not is that with that amount of powder in the case, the bullet is going to go down into the powder. Is that right? I'm using the data from the Sierra book and the max load of Varget is 24.0gr so I'm a little shy of that. Here's what I have:

case = 1.755"
Bullet = 1.070"
COAL = 2.255"

So if you do the math, the bullet has to go into the case .565" and the powder is just about up to the beginning of the neck so I'd say the bullet itself will be a good .200" into the powder. Is that even safe?

I guess I could use a different powder like 748 or H335 so it wouldn't be so high.

 

[308warbird]

80 grain SMK's are not intended to be loaded at mag length. Measure your throat and start at .020 off the lands. Expect an OAL around 2.450ish.

Your powder charge would be light for my rifle as well. 24.3 is my normal 600 yd load.

 

[Thumb]

I forgot to mention this is being shot in an AR-15 so I really can't go any more than 2.255 because of the magazine. Now I guess I could manually load the round into the chamber. I'm just going by what the Sierra book says to load to and that is in their AR-15 section. I understand what you are saying though about making the OAL longer and to about .020 of the lands.

My main concern was that the bullet is into the powder and would think that is not a good idea but then that's what Sierra is saying to do.

 

[308warbird]

I have shot a jillion of them in a AR15 seated at 2.455 and single loaded thru the port. I have never seen a 80 loaded at mag length.

Sierra made the bullet for the 600 yard slow fire portion of a XTC match, where it would be against the rules to load in any manner other than one at a time.

My Sierra manual is pretty clear about not trying to load the 80 at mag length. Call their tech support and ask them.

 

[Thumb]

I'll check into that, until then I'll put that load on the back burner, I've got plenty of other ones to do.

Thanks for your input guys, it's much appreciated.

 

[Martin52]

....with that amount of powder in the case, the bullet is going to go down into the powder. Is that right? .

A long drop powder funnel such as Forster makes might give you just a little more room in the case. It should allow the powder to settle in the case better and give a bit more headroom.

 

[Mega]

Or you can make one. Aluminium arrow shafts make good drop tubes for .22 Cal.

 

[gaboon]

Try some CFE223 if you get it. That should leave room in the case if stuck on mag length. Also you try to seat longer and see if it will fit in the mag and have some clearance.

 

[Thumb]

I'm working on it guys. I do have those other powders but I can also load to a longer OAL and just manually load it into the chamber. Right now I'm having a little problem on getting the chamber length to the lands because I keep getting different readings but the average for the 80gr bullet is 2.012 ogive between 5 different bullets. Given that chamber length, there is no way I can have a OAL of 2.550 with the 80gr bullet because the ogive with OAL of 2.550 round dimension is 2.044.

So if I want to try loading the 80gr bullet for this rifle, I'll have to have at the max an OAL of around 2.508 to have about .010 space to the lands.

I hope I am describing everything right and you understand what I'm getting at.

Another question that comes up is that I did load up some 77gr HPBT rounds with a OAL of 2.255 and have no problems with them at all. What I don't understand is that the 77gr bullet is .984" and the 80gr bullet is 1.070" which is a difference of .086" in length but they want you to make the OAL with the 80gr to 2.550 and the OAL of the 77gr to 2.255 which is a whopping difference of .295". Why so much of a difference in OAL for only 3gr difference?

Explanations or whatever insight anyone can give would be greatly appreciated.

 

[jhord]

Listen to what 308Warbird is saying. The 80SMK is not intended for, nor can you safely load it at, mag length. I suggest you stick one of the 80's in a fired case at mag length, and then you will see exactly why you cannot do it. Virtually none of the bearing surface of the bullet will be in the neck of the case. It will be close to dropping right thru the neck, with no tension at all. The 80 has a different shape, higher BC for the 600 yard line. The 77's ogive is a lot further forward, to get the bearing surface needed for mag length loading. You also have to have a chamber that is properly throated to utilize the 80's at common loaded lengths. (seated well out, to get powder capacity) For the avg. AR shooter there's not much difference between the 77 at mag length and 80's loaded long. A lot of top high power shooters/teams use the 77's all the way out to 600.

 

[Thumb]

I was listening and I am not trying to load it to mag length, I was just saying that with my barrel I guess I can not even load to the OAL that Sierra says to. I went back and looked at Sierra's data and they are using a Colt AR with a 20" barrel so I guess there is a difference in Chambers. I guess I'll pass on the 80gr then.

Anyone want to buy a box of 80gr bullets? ;D

 

[Preacher]

Any time you crunch powder into smaller pieces, your are changing the burn rate...
A little compression is OK but I would wonder about compressing it close to a 1/4" ...

 

[jhord]

I don't want to be argumentative but your posts sound like you are trying to, or want to, load an 80SMK at mag length. As long as you realize it can't be done, then I've made my point. Yes, .223/5.56 chambers vary considerably. For example a standard .223 chamber would not be suited at all to using the 80SMK's seated long or even the 77's at mag length, more than likely. While a 5.56 Nato or .223 Match would probably have no issues. It takes some fiddling around measuring, which you are doing, so you are on the road to figuring it out. You'll have no problem selling those 80's to somebody. I would suggest taking a look at Nosler 77's if you want to shoot that class of bullet. They are considerably cheaper than brand S if you buy them in bulk, and they shoot great. I use them over CFE223 and don't have to deal with compressed powder charges like you would with Varget. Good luck.

I was listening and I am not trying to load it to mag length, I was just saying that with my barrel I guess I can not even load to the OAL that Sierra says to.

 

[Thumb]

No arguments here at all and I did mention in about my 3rd post or so that I could just manually load the rounds into the chamber to shoot them. The Jack Carbine is a 5.56 Nato so I guess some of those are not able to accept the longer rounds either(chamber, not mag). I do and have have loaded the 77gr Sierra bullets and they shot OK but I seen the 80gr at the LGS and thought they might be better..thought ;D

Anyway like I said earlier, I'll put those 80gr into the vault or sell them. Just FYI though, here's a pic of the 77gr & 88gr bullets next to dummy rounds I made up with the right one being the 80gr bullet with an OAL of 2.550 and the left of course is the 77gr wc bullet in a OAL 2.255 round.