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More fun with 308 Win

wvfarrier

wvfarrier

Ignorant wretch
Full Member
Minuteman
Dec 7, 2012
3,501
6,578
West (By GOD) Virginia
#1
I have been doing more testing and toying with 308.

I have been using Alpha small rifle primer brass and CCI 450 small rifle magnum primers.

Rifleis a Zermatt Origin with 20" PVA M24 profile 1:10 twist.

MDT ACC Chassis.

My goal was 3000ft lbs of energy at the muzzle. This was due to a conversation I had with a buddy who just came back from a Safari. The company had a 3000ft lbs, at the muzzle, requirement for any rifle used for plains game. He took a 300wsm.

Powders were Varget and Power Pro 2000mr.

These loads are above book max but showed no pressure signs. I annealed every other firing. I worked the book pressure loads up using annealed starline srp brass.

I forgot to get pictures of the varget loads.

#1- Averaged 2605fps and .30" 5 shot group (No pressure Signs)

#2- Averaged 2614fps and .65" 5 shot group (No Pressure Signs)

#3- Averaged 2627fps and .88" 5 shot group (Very faint ejector mark)

#4- Averaged 2635fps and .55" 5 shot group (Again faint ejector mark, easy bolt lift)

#5- Averaged 2644fps and .23" 5 shot group (Ejector mark and at the very top of the bolt lift it was mildly sticky at the very top)

Power Pro 2000mr was a little lacking in the velocity dept.

My max load of 46.6 grains topped out at 2635 but should have been faster. My thought is that I am not getting complete powder burn. I found some partially burnt kernals in the barrel
.
The 46 grain load was absurdly accurate and had an average velocity of 2615.

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My 1moa sticker fell off the hole it was covering so I just shot at the hole.
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#7
3000 ft/lbs is doable in a 308 Win.
I have ran up to 4000 lbs in muzzle energy with a 30" 8 twist long action...and hybrid cases.
The 30" standard load with Lapua brass LR primer 2000MR 200 gr SMK is 2865 fps.
It does 2740 fps in a 9 twist 22" single load short action.

A 20" is on the short side for velocity, a 22" seems to be a good compromise for getting decent velocity.

So it all depends on what bullet you want to shoot, mag length, case type brass or hybrid.
Here's the 22" 308 with SA MDT mag length 2.970" 212 gr eldx at 2700 fps in load development, and 200 SMK in the mag 2700 fps, and 230 Atips at 2600 fps 9 twist 22" ...but with hybrid cases.
 

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#9
45-90 said:
3000 ft/lbs is doable in a 308 Win.
I have ran up to 4000 lbs in muzzle energy with a 30" 8 twist long action...and hybrid cases.
The 30" standard load with Lapua brass LR primer 2000MR 200 gr SMK is 2865 fps.
It does 2740 fps in a 9 twist 22" single load short action.

A 20" is on the short side for velocity, a 22" seems to be a good compromise for getting decent velocity.

So it all depends on what bullet you want to shoot, mag length, case type brass or hybrid.
Here's the 22" 308 with SA MDT mag length 2.970" 212 gr eldx at 2700 fps in load development, and 200 SMK in the mag 2700 fps, and 230 Atips at 2600 fps 9 twist 22" ...but with hybrid cases.
Click to expand...
Agreed on the barrel length for sure. Must admit though....I really enjoy this rifle. I have another action that may end up with a longer barrel on it.
 
#10
You may get 3000 ft-lb with these loads I use in a 16" 6 lb AR 10... if your 20" can pick up around 100 fps in 4 more inches of barrel.
Set your rifle up for sucess MDT detachable mag without center plate will feed 2.990" cartridges...2.860" is losing performance are the short barrels.

I lost over 40 fps per second using Small Rifle Primers in Lapua Palma brass over their standard LR primer brass...depending on the powder ya lose velocity with SR primers especially when using 50 grains of powder...ya have to add more powder with SR primer to get the same velocity, and S/D s are much better with heavy loads... SR primers are OK in warm weather and target loads with easier to ignite powders.
So I do not use SR primers in high performance loads.

Here are some lighter bullet loads that worked in my 16" AR 10 with 2.855" cartridges. With 4" of extra barrel you'll might reach 3000 ft-lbs.
Another example AR 10 200 gr SMK .715 g1 BC 2673 fps out of 18" AR 10 single load.

Its how you set up a 308 that gets 3200 to 3400 ft-lbs in 22" or 3600 to 3800 ft-lbs in a 30" long action...and more.
My 22" was built for $600, I chambered the new Rem Varmint contour 5R 9 twist barrel for heavy bullets 200 to 230 gr and a bunch of used parts...inleted for detachable mag , MDT detachable mag for 2.990" and muzzle brake...just "normal everyday 308 builds", that most gunsmiths do, you're missing out on a lot of extra performance.

I've built 8 308s from 16" to 30" and twists from 12 to 8 twist, light barrels to heavy palma...even hybrid cases...lots of experimentation with the 308.

Work up... use at your own risk.
 

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#11
I tested 4 more loads yesterday. All were well above book max. No pressure signs (except last load) but called it quits before physics got mad at me.
This was all done with Power Pro 2000MR, CCI 450s and Alpha SRP brass.

47.0- 2706fps avg (group .33")
47.2- 2716fps avg (group .25")
47.6- weirdly 2706fps avg again (.70")
47.8- 2756fps avg (group .55")
This last load has mild primer flattening and a mild ejector mark.

None of the SD's were in double digits.

I am not going to run any of these regularly but it was a fun experiment.

I will say it again though, Alpha Brass is AMAZING stuff.
 
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#14
CaptArab said:
Id like to see how far you could take the new eld-vt. Probably not a good rhino bullet but they should fly good.
Click to expand...
I purchased 500 174 elvt to test...but was running 177 at 3045 fps in 22" barrel and hybrid cases.
RL 17 was the powder.
2000 MR and RL 17 produce high velocities depending on bullet weight.
I'm working on 375 Raptor and 350 gr SMK which should arrive tomorrow. And 700 gr AP for the 510 whisper which arrived today.

The 174 gr should be over 3100 in the 30" 308 and hybrid csses.
 
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#17
Ok so i have more updates.

With PP2000MR I made it to 48.4 grains and quit there. I got a mild bolt stick at the very top of the lift, just enough to cause a hitch. Brass still looks good, these 30 pieces are at 9 firings, primers are still tight. I have been annealing after every firing. Also the previous session required trimming about .08 off.
48-averaged 2677 with 1.15" group
48.2- averaged 2683 with .75"
48.4- averaged 2704 and exactly 1" with mild bolt stick

1 more varget load got tested as well.
45.2- averaged 2686 and .89" no bolt issues or brass issues. May try another load of 45.4
 
#20
200 grs is a fairly heavy bullet for 308 and RL 17 is listed there...here's their data for the 200 gr.

I run the 200 gr SMK .715 G1 BC over 2700 fps in a 22" 9 twist Rem Varmint contour barrel in 308 at my mag length with RL 17.

Utilizing modified hybrid cases.

Dangerous...Do Not try these loads in any brass case.
These hybrid cases are made from 6.8x51 hybrid military cases, formed, neck turned, and annealed.
If you reload you can do the same with a little extra work...and ya don't have to run full power loads.

Also run the 230 Atip in the 22" barrel at 2600 fps with RL 17 and hybrid cases.

Set up your short action 308 with longer length detachable mags and 9 and 8 twist barrels...then add hybrid cases for even more velocity.

I have a 30" 8 twist long action 308 running 250 A tips at 2515 fps, 230 grs, around 2700 + fps.

Here's the 22" 9 twist 308 Win light "walking around rifle", shooting 200 gr SMK at mag length....using RL 17 and hybrid cases.

This 200 gr bullet is loaded out longer to over 2900 fps in the long action 30" heavy palma 8 twist 308.
This is my 308 heavy extreme rifle, which has hit 4000 ft/ lbs of muzzle energy.
 

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#21
How many firing you get on the hybrid cases? Have you had difficulty with them tearing up the actual chamber from the steel on steel contact?
I've been known to push the high nodes in my F T/R rifles from time to time. The juice wasn't worth the squeeze. Cases lasted about 4 firings. Lapua SRP Cases went 6-8. Groups opened up. I dropped back down to normal pressures and my score improved again. They hybrid cases are interesting but I've heard nothing but horror stories about problems with extraction, damaged chambers and short case life.
What's the scoop?
 
#22
moosemeat said:
How many firing you get on the hybrid cases? Have you had difficulty with them tearing up the actual chamber from the steel on steel contact?
I've been known to push the high nodes in my F T/R rifles from time to time. The juice wasn't worth the squeeze. Cases lasted about 4 firings. Lapua SRP Cases went 6-8. Groups opened up. I dropped back down to normal pressures and my score improved again. They hybrid cases are interesting but I've heard nothing but horror stories about problems with extraction, damaged chambers and short case life.
What's the scoop?
Click to expand...
You already decided hybrid cases are not for you...no further discussion is necessary. Don't use them, ...& be happy.

Can't be scaring the chambers because that portion of the case is all brass LOL...maybe .090" in transition from Stainless to brass actually enters the chamber.
So almost all of the S Steel head is hanging out of the chamber so your bolt can grab onto the case head for extraction.

The post is about "more fun with the 308"...there is alot of 308 fun to be had,... hybrid cases are just part of the fun.
I've made hybrid cases for 308, 358, 8.6 blkout, 375 raptor, 6.5 CM, 6 mm Dasher.

How about some accurate 308 subs...or hollow pointed 30 Mauser 86 gr jacketed pistol bullets out of a 30" 8 twist 308.
Inquiring minds want to know...
A variety of calibers with hybrid cases, some with very heavy bullets...including a 308 250 Atip at 2515 fps.
 

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#23
I tried some 175 bthps yesterday with PP 2000MR. I, quite literally, ran out of powder capacity before I had pressure signs. Top velocity out of my 20" barrel was 2825fps with a 10 SD and a 5 shot group of .66". It did stretch the case necks by an average of .013

I am going to try this same load with the 180 grain Sierra Gamekings once they arrived
 
#25
moosemeat said:
How many firing you get on the hybrid cases? Have you had difficulty with them tearing up the actual chamber from the steel on steel contact?
I've been known to push the high nodes in my F T/R rifles from time to time. The juice wasn't worth the squeeze. Cases lasted about 4 firings. Lapua SRP Cases went 6-8. Groups opened up. I dropped back down to normal pressures and my score improved again. They hybrid cases are interesting but I've heard nothing but horror stories about problems with extraction, damaged chambers and short case life.
What's the scoop?
Click to expand...
That is a good question, especially the way stainless likes to gal.
 
#27
45-90 said:
"Stainless likes to gal"??
" gal"... is a girl... 👧 according to the dictionary.
Click to expand...
This from the guy who said using nickle plated brass would mess up your chamber. 🤣🤣🤣

Couldnt figure out what it meant because of a L? 😳😳 Never took you for being real sharp, I guess. 😉

I meant stainless likes to gall. Do you disagree? 🤣🤣
 
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#28
Can't cover up stupid mistakes and crushed ego...with emojis...🤣.

In this case, lol, I do disagree because almost no stainless touches the chamber to cause any galling...like 99.9%. Most of the SS head hangs in the air, out of the chamber and flat against the bolt face.

Speculation on something you heard about metals, doesn't count much on a product you obviously know nothing about.

With millions of rounds fired in military weapons, and much of thousand fired by me in boltguns and autoloaders...galling is not a problem.
 
#29
45-90 said:
Can't cover up stupid mistakes and crushed ego...with emojis...🤣.

In this case, lol, I do disagree because almost no stainless touches the chamber to cause any galling...like 99.9%. Most of the SS head hangs in the air, out of the chamber and flat against the bolt face.

Speculation on something you heard about metals, doesn't count much on a product you obviously know nothing about.

With millions of rounds fired in military weapons, and much of thousand fired by me in boltguns and autoloaders...galling is not a problem.
Click to expand...
Crushed egos. 🤣🤣🤣

If you think stainless doesn't gall, your about as dumb as you would have to be to think you hurt my feeling because you found a misspelled word in my post.

You're literally the retard savvy reloaders make fun of talking about "safe in my gun." Literally the kind of dude that is the reason we don't like to sit next to people at the range.

Military weapons mostly have coated barrels. No stainless on stainless contact.
 
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#31
supercorndogs said:
Crushed egos. 🤣🤣🤣

If you think stainless doesn't gall, your about as dumb as you would have to be to think you hurt my feeling because you found a misspelled word in my post.

You're literally the retard savvy reloaders make fun of talking about "safe in my gun." Literally the kind of dude that is the reason we don't like to sit next to people at the range.

Military weapons mostly have coated barrels. No stainless on stainless contact.
Click to expand...
Totally crushed your ego...what a fool, the more you spout off your mouth, the worse it gets for you. A low IQ person.

All ego and little brains... here's proof.
I did not say stainless does not gall.
Can't read either?...
Arguing against your ignorant foolish self, presents your low IQ to the world...like others here.

I said in this instance, there will be no galling...because there is almost no contact with the stainless case head by the chamber...fact...the case body is all brass, and the case head only is SS.
You have No experience with hybrid cases, but "think" you are the expert on the subject.
Spreading false information and foolish ideas with your lack of knowledge and NO experience on the subject is a big negative.
So YOU present yourself as an ignorant egotistical fool...only you can change that.
 
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#32
wvfarrier said:
I resized a couple of those binary cases and they held 1.1 grains less H2O than the Alpha Brass I have been using. Thats pretty substantial
Click to expand...
Good to weigh them for water capacity.
The hybrid cases will usually gain a fair amount of capacity after firing...depending on your chamber they usually equal or surpass other case volumes...but newer hybrid cases have been showing less case capacity then the first years production.

It's been reported that LC is making them now, and they are a bit heavier, with 23 and 24 date yrs stamped on the case heads.

My older Sig hybrid cases with no date stamp measure 58.3 to 58.8 gr of water capacity after fireforming. If you see any load data and your cases are of less capacity your maximum load must contain less powder...
This 308 test load does indeed contain 56.1 grs of powder...this was over 3500 fps in a 22" barrel.
And a variety of powders behind the 212 gr eldx in 308 with hybrid cases fulfilled on a request for that bullet and max loads were refired for different powders in the 48 to 50 grs area.
Case capacity changes make a huge difference in pressures....so beware, and always check yours vs the other guys in the data.

The hybrid cases also usually need trimmed to length after the first firing.
 

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#33
45-90 said:
Good to weigh them for water capacity.
The hybrid cases will usually gain a fair amount of capacity after firing...depending on your chamber they usually equal or surpass other case volumes...but newer hybrid cases have been showing less case capacity then the first years production.

It's been reported that LC is making them now, and they are a bit heavier, with 23 and 24 date yrs stamped on the case heads.

My older Sig hybrid cases with no date stamp measure 58.3 to 58.8 gr of water capacity after fireforming. If you see any load data and your cases are of less capacity your maximum load must contain less powder...
This 308 test load does indeed contain 56.1 grs of powder...this was over 3500 fps in a 22" barrel.
And a variety of powders behind the 212 gr eldx in 308 with hybrid cases fulfilled on a request for that bullet and max loads were refired for different powders in the 48 to 50 grs area.
Case capacity changes make a huge difference in pressures....so beware, and always check yours vs the other guys in the data.

The hybrid cases also usually need trimmed to length after the first firing.
Click to expand...
Thats good info. Thank you
 
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#34
45-90 said:
Totally crushed your ego...what a fool, the more you spout off your mouth, the worse it gets for you. A low IQ person.

All ego and little brains... here's proof.
I did not say stainless does not gall.
Can't read either?...
Arguing against your ignorant foolish self, presents your low IQ to the world...like others here.

I said in this instance, there will be no galling...because there is almost no contact with the stainless case head by the chamber...fact...the case body is all brass, and the case head only is SS.
You have No experience with hybrid cases, but "think" you are the expert on the subject.
Spreading false information and foolish ideas with your lack of knowledge and NO experience on the subject is a big negative.
So YOU present yourself as an ignorant egotistical fool...only you can change that.
Click to expand...
I bet the stainless doesn't touch the bolt face either, huh....🤣🤣🤣

I didn't say anything about the chamber cheif. Although a rough measuring of a couple cases tells me to call bullshit on your 99.9% of the stainless case head doesn't touch the chamber though.

It would to seem to add to the likleyhood of damaging the bolt face chambering rounds a little tight on headspace. Granted I have experienced any, that doesn't mean it can't happen and isn't so.rthing to keep in mind.

20250814_045156.jpg
 
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#35
You appear to be trying for 1st place for the most damaged egotistical idiot on the site.

You Can't read...I already said "the SS case head is against the bolt face"....go back and reread it.

This is a 308 cartridge in a 308 chamber...notice most of the solid head is not supported but outside of the chamber.

There is not a problem with galling, as stated. Nothing you show I don't already know...I work with these hybrid cases in a variety of chambers.

But you wouldn't know that, cause you don't use hybrid cases.

No one cares if you like hybrid cases or not, there are positives and negatives to most everything but galling is not a problem here, and proven by use, plus there is almost no SS in contact with the chamber as stated, most of the SS case head is outside the chamber, as pictured.

If your ego didn't get in the way you might learn something....instead your showing your increasing stupidity and lack of subject knowledge.
Then you continue pressing on, presenting even more stupidity...
 

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#36
45-90 said:
You appear to be trying for 1st place for the most damaged egotistical idiot on the site.

You Can't read...I already said "the SS case head is against the bolt face"....go back and reread it.

This is a 308 cartridge in a 308 chamber...notice most of the solid head is not supported but outside of the chamber.

There is not a problem with galling, as stated. Nothing you show I don't already know...I work with these hybrid cases in a variety of chambers.

But you wouldn't know that, cause you don't use hybrid cases.

No one cares if you like hybrid cases or not, there are positives and negatives to most everything but galling is not a problem here, and proven by use, plus there is almost no SS in contact with the chamber as stated, most of the SS case head is outside the chamber, as pictured.

If your ego didn't get in the way you might learn something....instead your showing your increasing stupidity and lack of subject knowledge.
Then you continue pressing on, presenting even more stupidity...
Click to expand...
If anyone asks a basic question you get super butt hurt. You are the one all us randoms just reading for info, see as the sensitive snowflake. Quit acting like a Spanish soccer player. We don’t care about your personal history of hybrid case drama. Bottle that shit up like a man, and just talk about how they work for you.
 
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#38
Emerson0311 said:
If anyone asks a basic question you get super butt hurt. You are the one all us randoms just reading for info, see as the sensitive snowflake. Quit acting like a Spanish soccer player. We don’t care about your personal history of hybrid case drama. Bottle that shit up like a man, and just talk about how they work for you.
Click to expand...
I talk about how they work for me and some of the difficulties, but that's unacceptable to the dipshits who know nothing about hybrid cases...they interject with ridiculous statements, and moronic opinions that take away from the quality of the subject...it happens all the time on this site.
Then they argue on their ridiculous opinion with no knowledge of the subject.
Don't even read the response many times.
Just keep up the moronic egotistical, chest bumping, highschool bullshit.

Can't educate them cause of the know it all ego, and it's gotta be true cause they read it online, or heard if from a shooting buddy.

Just like the 7mm Backcountry thread turned into the "gay caliber", by the comical experts here, all those who don't like the steel case idea, totally degrading it in any way they can.
Ruining any real discussion.

But I want to see what it can do... by reports from New owners on what it is really capable of.
Their real experiences, positive and negative issues of the new round and its steel case.

But the whole thread goes into moronic high-school bullshit in a hurry, especially if the new cartridge is better in some way then their favorite.
Seems at least 50% of the posts are like that.
 
#39
Some interesting stuff in here, especially the hybrid cases. I must have been living under a rock and spending too much time in the bear pit because I have missed these!

Been saying for a while that the next generations of rounds and “leaps forward” will be coming from increased pressures and new generations of powders, cases and barrels that will make for much higher velocities and energies.

Need to really re-read all this, but definitely following. Especially the case technology! Very interesting!

Cheers, Sirhr

PS… this is the sort of stuff that keeps SH right on the forefront of the precision rifle world. Wildcatting and experimenting is well into its second “golden age” and it’s happening right here!
 
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#40
Those who wanted some 308 Win data for the Hornady 174 gr ELD-VT velocities from the hybrid case.
This is a good load fastest tested today with low S/Ds 3086 fps with RL 17.

Also shot some 174s with Varget = 2858 fps, RL 15 = 2877 fps from the 22" barreled rifle.
 

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#41
sirhrmechanic said:
Some interesting stuff in here, especially the hybrid cases. I must have been living under a rock and spending too much time in the bear pit because I have missed these!

Been saying for a while that the next generations of rounds and “leaps forward” will be coming from increased pressures and new generations of powders, cases and barrels that will make for much higher velocities and energies.

Need to really re-read all this, but definitely following. Especially the case technology! Very interesting!

Cheers, Sirhr

PS… this is the sort of stuff that keeps SH right on the forefront of the precision rifle world. Wildcatting and experimenting is well into its second “golden age” and it’s happening right here!
Click to expand...
The first I know that this has been tried was on the 277 Fury that sig announced in 2019. I don’t know if the idea was tried previously.

I worked for a tool manufacturer and I personally made a pile of tooling for these in 2018/2019. We sent the tooling to a subcontractor that was making the stainless heads that ended up at sig. there was more than one shop making the stainless heads, all trying for a contract I’m sure.
Made for 5.56 and also 7.62

I have never loaded them or tried them. But would like to someday. Super cool idea in my opinion!
 
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#42
Makinchips208 said:
The first I know that this has been tried was on the 277 Fury that sig announced in 2019. I don’t know if the idea was tried previously.

I worked for a tool manufacturer and I personally made a pile of tooling for these in 2018/2019. We sent the tooling to a subcontractor that was making the stainless heads that ended up at sig. there was more than one shop making the stainless heads, all trying for a contract I’m sure.
Made for 5.56 and also 7.62

I have never loaded them or tried them. But would like to someday. Super cool idea in my opinion!
Click to expand...

And seems Sig has a contract to make a ton of cases for the .mil.

Issues in 2022 or so.

The idea is not exactly new. All kinds of stuff have been tried back to the early days of breechloading. (Snider Enfield rounds!). And it’s been a common thing in artillery cases.

What “is” new are the manufacturing techniques and metallurgical advances that are making possible stuff like this. And the ability to scale it down to small rounds economically.

I’ve brought up the idea of 3D printing powder in cases before, which could allow combinations of fast and slow powder and even create explosive “lenses” in cases. Essentially progressive ignition and burns and focusing the ignition away from walls and into moving the projectile. It’s all theoretical, and would require more than my “scratchpad” stuff. But as the saying goes, there is a pony in there somewhere.

IMHO Pressure is the next frontier. Better case technology is a big step. SAAMI better start making some higher-rated testing machines soon!

I’ll do some more digging tomorrow’and give this thread a detailed read when not on this silly phone. But this has me lying awake thinking of possibilities!

Sirhr
 
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#43
I hit 2850 with the 180 grain Gamechanger using Power Pro 2000MR, Alpha SRP brass and CCI 450s. I blew my first primer with this load however that piece of brass is on its 15th firing all of which have been over book max. This is from a 20" barrel. Bolt lift and extraction still smooth on the origin action. Accuracy was acceptable at 1" 5 shot group. Several other groups were smaller so will focus on refining those. SDs were all higher than I wanted.
 
#45
Just going off memory here but I believe a impact has a .940 tennon length and a .948 headspace. 0.150 bolt nose recess. So .330 minus .158 equals 0.172" of case in the physical chamber. Does that math check out for actual gun smiths? I believe most actions with a "3 rings of steel" recessed bolt face are about the same.

Another way of looking at it is 0.130" of steel case above the .200" line of the case in the chamber. The .200" line with brass cases is the spot i measure case head expansion of fired brass at on traditional cases to check expansion and pressure. Are you seeing much/any growth at this point on your fired hybrid cases?
 
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#46
.172" plus the chamber radius .015" ? of the sold case head is Not supported by anything.

The 3 rings of steel do not support any of the solid head that sticking out, ...from the chamber radius to the bolt face.
The .480" dia bolt face recess does not support the .469' to 470" case head.

Three rings of steel are there to contain the burst or explosion along with the vent in the action.... in an over pressure event, so big chuncks of brass or steel don't enter your face...but the finer chunks of brass will escape with enough velocity to penetrate your face and eyes, along with the high pressure gas released.
But if the bolt recess shatters, what is not contained by the counter bore in the barrel it's coming for your face along with the brass case head fragments now in much larger pieces to do some real damage to your body.

The .700" X.150" counter is usually. 155" or a bit more deep...clearence all around the individual bolt. There is a radius on the rifle chamber not taken into account.
Everything has a bit of clearance added so a little debris won't shut down the guns operation.
The 3 rings of steel are containment vessels, a safty measure,...as no actual support for the solid case head exists as it's sticking out of that chamber.

The majority of the expansion is around the .200" line cause the brass is thined out, now it can expand and seal the chamber of your rifle as designed.

This is what your FL sizing die sizes down to make clearence between the chamber and newly reloaded round....most of the solid case is not sized.
As you have the rim extractor groove and die champher taking up that area of the solid head.
While the solid head has no expansion or very little like .0005" to .0007" too much above that and primers begin to fall out of their pockets much sooner than expected, but some will run over .001" case head expansion. Your call...

Stainless expands at higher pressures, that's why it's used in hybrid case heads...
 

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#47
Another example of solid head has no support .
This is a recut 9mm chamber .001" deeper than factory to clean up the dia of worn out chamber reamer used as it wouldn't chamber unless bullets were undersized.

Notice the large chamber lead in angle causing even less case support.
But it will handle +P loads well above standard pressures into the 40,000 psi
area.
 

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