Issues with Lapua Brass (Updated with Pics)

[johnsta]

Hello...

I have a custom .308 with a 22" Bartlein m24 barrel. According to the company that made my rifle, it has a very tight match chamber. I have always been able to get superb accuracy with Winchester brass, IMR 4895 and the 178 BTHP. I have a lot of Lapua brass and have decided to work a load for Lapua brass with Varget and IMR 4064. I have large quantities of those powders and wanted to find a secondary load to use in the rifle just in case components get scarce.

My problem is with the lapua brass. After using a FL sizing die to re-size the brass I am able to chamber the brass with no tension closing the bolt. However once I fire the round, it is almost impossible to eject the case. Mind you, I am well below max load recommendation and closer to the starting to mid range recommendations. I was told that Lapua brass is very thick and does not perform well in chambers that are extremely tight.

I am under the impression that brass is the same dimensions on the outside, and the difference is in the internal capacity. Am I wrong?

Could someone help me understand how, if I run my winchester brass and my Lapua brass through the same sizing die, that the two cases would have different external dimensions?

Does fire forming help? Would a small base die help make the Lapua brass work?

I suppose I could sell all my lapua brass and stick with the winchester which is what I am leaning toward. However I like Lapua brass damnit!

Thanks for your help!

 

[remiglockoholic]

I'll take the brass!!!

 

[remiglockoholic]

All jokes aside redo your pressure test, and then reassess. I've been using Lapua exclusively since I exceeded case life of the first few Federal and Remingtons I bought as commercial ammo. Things I've seen on this site as pet loads for others using Winchester brass have shown pressure signs when I've duplicated with Lapua.

 

[LawnMM]

The internal capacities are different, maybe 44gr of Varget is awesome in Winchester btass but in Lapua it may be over pressure. That it chambers fine but sticks on extraction sounds like over pressure. Post a pic of some of your case heads that stuck, I'll bet you have other signs as well.

 

[Temp9]

Being below max load does not guarantee safe pressures. If you are getting heavy bolt lift after firing, that should be interpreted as a pressure sign and should show up in the case head. How do the case heads look?

 

[EasyGravy]

I had this same issue going from hornady match to lapua. As LawnMzm said.

 

[thespecialist]

It's possible that the chamber dimensions are too tight in the neck for you to run Lapua brass unless you turn the necks. Take a piece of once fired Lapua and see if you can slip a projectile into the neck, if not then you'll have to turn the necks down a couple thousandths to get them the room they need. What happens is that the neck doesn't release the projectile freely if the neck is too tight, causing pressures to rise significantly. If I remember correctly, Lapua 308 necks are around .015-.002" thicker than Winchester. Not much, but it's .003-.004" overall on the outside of the loaded round. Now if your chamber is cut for Winchester brass to have .003" neck clearance, and you stuff a case in there that's .003" bigger in the neck than the Winchester brass, you can see where that extra girth turns into an issue.

ETA: If the necks aren't pinching the bullet, you need to back down and rework the load.

 

[mdmp5]

Regardless of your previous load or published data, you need to step it down. Take it down at least 1 grain and try that

 

[RyeDaddy]

It's possible that the chamber dimensions are too tight in the neck for you to run Lapua brass unless you turn the necks. Take a piece of once fired Lapua and see if you can slip a projectile into the neck, if not then you'll have to turn the necks down a couple thousandths to get them the room they need. What happens is that the neck doesn't release the projectile freely if the neck is too tight, causing pressures to rise significantly. If I remember correctly, Lapua 308 necks are around .015-.002" thicker than Winchester. Not much, but it's .003-.004" overall on the outside of the loaded round. Now if your chamber is cut for Winchester brass to have .003" neck clearance, and you stuff a case in there that's .003" bigger in the neck than the Winchester brass, you can see where that extra girth turns into an issue.

ETA: If the necks aren't pinching the bullet, you need to back down and rework the load.

This. One of my rifles has a neck that's too tight for Lapua but does well with Winchester. Symptoms are exactly like yours unoess I turn the necks.

 

[Deadshot2]

Lapua brass definitely holds less powder than brass like Winchester. You have to be real careful with Lapua brass as it often doesn't show some of he early pressure signs like an ejector mark or hard bolt lift like some of the softer brass does.

It might be a good idea to start from the beginning by making a cast of the chamber using cerro safe (wood's metal). This will give you some actual dimensions of the neck area of the chamber and you can then see whether or not the necks need to be turned. If so the good news is that it only needs to be done once for that batch of brass.

BTW, a chamber cast will also tell you how long you can let your brass grow before having to trim it. Longer brass minimizes the amount of carbon ring that builds up in the front of the chamber. Just leave .010-.015" of clearance for safety.

 

[RTH1800]

Check to see if a bullet can be inserted into the case neck by hand after firing. If it is hard or cannot be done, you need to turn necks or use other brass.

 

[rduckwor]

I haven't had any commercial WIN cases to work with, but I believe that they make the BHM cases so they should be very close to Commercial WIN.

Case Capacities in Grains of Water:

 

[johnsta]

Wow, a lot of great information here. Thank you very much to everyone who has responded.

I didn't suspect the necks, but this all makes perfect sense. I really wasn't wanting to neck turn!

I won't be home until tonight so I will test the necks on a fired case with a bullet then. Here are some pictures:

 

[mrbig]

the shiny spot on the UA and PU of lapua indicates to me at least 1 gr over max and probably 2 grs over a safe working load,,it takes a hot load to get flow and ejector swipe in Lapua brass,,

 

[Geno C.]

That looks like a cratered primer... High pressure perhaps? like stated above, check to see if you can get a bullet in the case after firing. My vote is too tight of a neck for Lapua brass. Neck turning is the solution. The good part of it is at least you'll have uniform necks now

 

[johnsta]

That looks like a cratered primer... High pressure perhaps? like stated above, check to see if you can get a bullet in the case after firing. My vote is too tight of a neck for Lapua brass. Neck turning is the solution. The good part of it is at least you'll have uniform necks now

Yea, looks like I will be neck turning. How much of the neck do I need to remove?

 

[Jaxdialation]

Lapua necks can be a real bear. Like the OP, I just can't get excited about neck turning. I only use lapua,
but would dump it in a heartbeat if I had to turn all of the necks on 308 260 and 243AI loads.

Your 308 loads are obviously too hot. I'm NOT convinced you have a neck thickness problem.
Let us know what you figure out!

I've deliberately avoided "tight" chambering. I don't see the point. Early 260 shooters all went ape
for this kind of thing, then quickly learned the down-side.

Let us know what you figure out. I'd rather take a beating than neck turn brass!

Another idea not mentioned yet is to call the gun plumber up and ask his advice.

 

[swamp donkey]

Primer cratering, flowing brass on the head, and what looks like a sharp radius to the shoulder, that's three over pressure signs I see.
What are the velocities like compared to your usual loads ?


Regards

Pete

 

[mjh30]

Primer cratering, flowing brass on the head, and what looks like a sharp radius to the shoulder, that's three over pressure signs I see.
What are the velocities like compared to your usual loads ?


Regards

Pete[/QUOT

OP, I will echo what Pete said and Mrbig, those loads are way too hot. If its a custom built rifle there should be no problem calling and finding out what reamer they used. I suggest starting at the bottom of the load recommendation and see what happens.

 

[Geno C.]

Yea, looks like I will be neck turning. How much of the neck do I need to remove?

If this turns out to be the problem then turning to the same thickness of your win brass is a for sure way to fix it. Calling the builder to find the neck on the chamber is best. Then take the diameter of your loaded round with the Lapua brass. You'll need to turn your necks enought to get at minimum .001" clearance. FWIW I run .002" on my only gun I turn brass for.

 

[Mad_Charlie]

If this turns out to be the problem then turning to the same thickness of your win brass is a for sure way to fix it. Calling the builder to find the neck on the chamber is best. Then take the diameter of your loaded round with the Lapua brass. You'll need to turn your necks enought to get at minimum .001" clearance. FWIW I run .002" on my only gun I turn brass for.

I thoroughly agree, but I do think that the builder should have given the OP the spec's for the rifle, instead of just letting him fend for himself.

 

[Geno C.]

That's very true. Especially if it was something like this that could cause a problem

 

[918v]

Before to start cutting on the brass, what is your fired neck diameter?

 

[johnsta]

Before to start cutting on the brass, what is your fired neck diameter?

Of the two pieces of brass shown in the pictures (the only ones I fired), the neck diameter for both is .341" . How does this compare to others?

Edit: Winchester brass is .341" as well.

 

[Steel head]

Before to start cutting on the brass, what is your fired neck diameter?

This is a good track.
Loaded and fired neck diameters for the Lapua and Win brass?

 

[johnsta]

Check to see if a bullet can be inserted into the case neck by hand after firing. If it is hard or cannot be done, you need to turn necks or use other brass.

So I can push a projectile through the Lapua brass, however it doesn't fall right though and into the case. There is moderate tension when I push the bullet through.

The projectile falls right through the Winchester brass when I drop a bullet through a fired case.

 

[Geno C.]

Ding ding. I think we have a winner!

 

[FCS]

You probably need to do a clean up neck turn. Probably have a 0.342" diameter neck in chamber, Lapua loaded round is typically 0.339 to 0.340 so only 0.001-0.0015" clearance a side. I prefer a bit more then that in my tactical / field rifles.

If you fire a round loaded in Lapua brass, make sure when you extract fired brass that it does not smack lug raceway or ground, and you can not easily slide a bullet through neck.....you don't have quite enough clearance IMHO. You'll want to neck turn for a loaded neck diameter of 0.338", 60% clean up cut will probably be more then enough to resolve your issue if a bullet will not easily slide through neck of fired case.

 

[johnsta]

You probably need to do a clean up neck turn. Probably have a 0.342" diameter neck in chamber, Lapua loaded round is typically 0.339 to 0.340 so only 0.001-0.0015" clearance a side. I prefer a bit more then that in my tactical / field rifles.

If you fire a round loaded in Lapua brass, make sure when you extract fired brass that it does not smack lug raceway or ground, and you can not easily slide a bullet through neck.....you don't have quite enough clearance IMHO. You'll want to neck turn for a loaded neck diameter of 0.338", 60% clean up cut will probably be more then enough to resolve your issue if a bullet will not easily slide through neck of fired case.

Thanks. Being that I clearly have pressure issues as well, would turning the necks as you described lower my pressures?

These were the loads I was planning on trying before I stopped (after 2 lol) as I was planning on preforming OCW testing:

Lapua Brass, Hornady 178 BTHP, Fed 210M, Varget loaded to 2.800: 43, 43.3, 43.6, 43.9, 44.2

Lapua brass, Hornady 178 BTHP, Fed 210M, IMR 4064 loaded to 2.800: 43.1, 43.4, 43.7, 44, 44.3

Thank you very much for all those who have helped me figure this problem out. You guys are great people.

 

[blackfoot]

Sorry but I believe the neck clearance is most likely a non issue, unless you have a non SAMMI neck diameter chamber. Brass springs back 1 to 2 thousandths after firing, so you can have plenty of neck clearance and still not be able to insert a bullet into a fired case. Hunter BR guys back in the day used 1 thou total clearance in what they called "fitted necks". Didn't even have to size the case, just load after firing and have adequate neck tension. If the brass is thicker in the neck, as your test indicated, then it's most likely thicker throughout, indicating less capacity than Win brass and thus more pressure with the same charge.

 

[BC 6.8]

Given your fired brass dimensions, you shouldn't have to turn the Lapua brass unless your loaded round neck OD is greater than 0.339". My loaded Lapua rounds are 0.338" with unturned brass. Make sure that your chamber is clean and also make sure that your resized brass is not longer than 2.015" which is SAAMI max. From the pictures it looks like an over pressure load which can be caused by several issues including too much powder or brass that is too long.

 

[FCS]

Pressure issue can easily be caused by fact that neck can not expand enough to let go of bullet completely, that will boost your pressure quickly! If not enough neck clearance for neck to properly release bullet, then turning neck can relieve pressure issue. What is a loaded round neck diameter for 178 in Lapua brass?

What is OAL to touch lands with 178 Hornady BTHP?
If you have a short lead chamber, 178 BTHP is touching lands with an OAL of 2.840" or less, you'll most probably be topped out around 43.6 gr of Varget in Lapua brass from a safe, working pressure standpoint.
You'll be roughly 0.7 gr less powder in Lapua vs Win/BHA brass for same pressure / velocity due to smaller case capacity, emphasis on roughly 0.7 gr less. I'd start down 1.5 gr from Win brass in Lapua and work up to desired velocity, accuracy w/o seeing any pressure signs to be on safe side.

Reamer print to verify body diameter, neck diameter , freebore length and lead angle would all be very useful information to have. You can reverse engineer it but having those dimension up front would clear up a fair number of your questions.
What dimension(s) is the gunsmith running "tight"?

 

[Coletta]

OP, do you know what reamer was used?

 

[918v]

Your loads are too hot. I load 42grs of 4064 in a Lapua case under a 175SMK. And I have a generous chamber. You have enough clearance in the neck to avoid neck turning. Cut back on the powder charge.

 

[ZombieMonkey]

You really need to know what reamer was used as the tight neck can lead to pressure spikes. You may not feel it while chambering the round like you would with a case body being too large. You most definitely have some pressure issues going on, the question is where does the problem originate. Lapua brass itself doesn't usually show pressure signs nearly as quickly as some of the other brass I've worked with. I can run 44.2 gr of varget under 175 smk or 178 AMAX all day long in a number of 308s with Lapua brass even at temperatures well over 100 degrees, but I've never seen any of my Lapua brass get to be in that bad of shape even while testing loads higher than those.

Load an empty Lapua case and a Winchester case that you've been using, compare all of your dimensions. This should be pretty apparent. Check your trim lengths and confirm that you have not begun to inadvertently jam a bullet while switching to the new brass as both can play hell with pressure spikes.

Forget the small base die idea you had, that's not going to do anything for you in this case.

 

[918v]

Lapua brass has less internal capacity than Winchester. It is close to FC. In my testing I need 1gr less of 4064 to reach the same velocity (42 vs 43grs).

 

[ZombieMonkey]

Lapua brass has less internal capacity than Winchester. It is close to FC. In my testing I need 1gr less of 4064 to reach the same velocity (42 vs 43grs).

Seems to be the trend that most of us see.

 

[johnsta]

Pressure issue can easily be caused by fact that neck can not expand enough to let go of bullet completely, that will boost your pressure quickly! If not enough neck clearance for neck to properly release bullet, then turning neck can relieve pressure issue. What is a loaded round neck diameter for 178 in Lapua brass?

What is OAL to touch lands with 178 Hornady BTHP?
If you have a short lead chamber, 178 BTHP is touching lands with an OAL of 2.840" or less, you'll most probably be topped out around 43.6 gr of Varget in Lapua brass from a safe, working pressure standpoint.
You'll be roughly 0.7 gr less powder in Lapua vs Win/BHA brass for same pressure / velocity due to smaller case capacity, emphasis on roughly 0.7 gr less. I'd start down 1.5 gr from Win brass in Lapua and work up to desired velocity, accuracy w/o seeing any pressure signs to be on safe side.

Reamer print to verify body diameter, neck diameter , freebore length and lead angle would all be very useful information to have. You can reverse engineer it but having those dimension up front would clear up a fair number of your questions.
What dimension(s) is the gunsmith running "tight"?

Sir -

I just measure the neck diameter of some loaded rounds with the Lapua Brass. It was pretty consistent at .3375". The Winchester brass was consistent at .3325".

So, if the necks on my loaded rounds are .3375, and the fired case neck diameters are .341", that is a difference of .0035". Wouldn't that rule out neck issues? Is .0035" not enough to release the bullet without tightness? The Winchester necks have an expansion of about .0085" which is twice that of the Lapua. Is that the issue or not?


Or could it be I need to substantially lower charge amount in the Lapua brass?

I really appreciate the help guys. I apologize if these issues are rookie. I thought I was experienced...ha.

I will be contacting the rifle maker tomorrow.

 

[918v]

You need to reduce the load, not the neck diameter. Your fired brass measures .341" but that excludes the .001" spring back. Your chamber has a .342" neck giving you .004" of clearance. That is plenty.

 

[918v]

You got to understand the case takes up room in the chamber. The smaller the chamber the more room the case takes up. A tight neck chamber raises pressures because it reduces chamber volume. A 172gr Lapua case takes up more space than a 158gr Winchester case. Reduce the load.

 

[FCS]

Sir -

I just measure the neck diameter of some loaded rounds with the Lapua Brass. It was pretty consistent at .3375". The Winchester brass was consistent at .3325".

So, if the necks on my loaded rounds are .3375, and the fired case neck diameters are .341", that is a difference of .0035". Wouldn't that rule out neck issues? Is .0035" not enough to release the bullet without tightness? The Winchester necks have an expansion of about .0085" which is twice that of the Lapua. Is that the issue or not?


Or could it be I need to substantially lower charge amount in the Lapua brass?

I really appreciate the help guys. I apologize if these issues are rookie. I thought I was experienced...ha.

I will be contacting the rifle maker tomorrow.

Loaded round neck diameter of 0.3375" (with a micrometer or with calipers?) and fired neck diameter of 0.341, not a clearance issue. Powder charge is too high, need to drop charge and work back up.

Have you chronographed this load?

 

[johnsta]

Loaded round neck diameter of 0.3375" (with a micrometer or with calipers?) and fired neck diameter of 0.341, not a clearance issue. Powder charge is too high, need to drop charge and work back up.

Have you chronographed this load?

I am in between chronographs right now so I did not.

 

[thespecialist]

Loaded round neck diameter of 0.3375" (with a micrometer or with calipers?) and fired neck diameter of 0.341, not a clearance issue. Powder charge is too high, need to drop charge and work back up.

Have you chronographed this load?

Agreed, it's 100% not a neck clearance issue.

Op, drop the charge 1.5 grains or even 2 and rework it. You're way past sane pressure levels there.