Haven't shot a deer yet either, but I load up with either the 90 gr game king or the hornady 87 gr spire point in anticipation of shooting one.

The brown truck left 8lbs of  Accurate LT-32 on the front door step Friday. Is supposed to have a burn rate between H/IMR 4198 and A2200-REL-7.

I loaded up some ammo this afternoon and hope to get to the range tomorrow.  LT-32 is a fine-grained extruded powder, and meters well through the powder measure. It does not quite have the same load density as a ball powder like A2200.

Has anybody have any experience with this powder?

Sorry to piggyback on your post, but I was looking at the data for LT-32 and noticed the 5.56 max grains of powder was greater than the 223 max. Is this because the 5.56 casing is stronger/larger than the 223 brass?  If so, would it be possible to gain more fps with the 25/223 using 5.56 brass rather than the Winchester 223 brass I am currently using?  I know everything is subjject to my barrel, but in theory is that possible?  Just curious as to what brass everyone is using.

My experience so far is that I am getting better groupings with the hotter loads of AA2200. The best loads show a little primer cratering.  It wasn't bad in the cooler weather, but started when the hot weather came on this summer. I am using Rem primers.

556 loads are to 62000-63000 psi and 223 loads are to 52000-55000 the cases are the same. the chambers of a 556 has more lead and more throat so it can handle more pressure.

i load most of my 223 wildcats to the hot side with out issue

I have Redding 25x45 dies now, so I thought I would offer up my CH4D 25/223 dies here first for anyone that might need them. Lets say $50 shipped, prefer a sterile Pp gift.

[email protected]

Can't wait to see some data.  I forget, do you have a 20" built to test, or just your 16" still?

IM sent.

Any word on the powder testing?

It rained on sunday so I did not get to the range.  I am going to try and get to the range tomorrow.

Any word on the powder tests?

I also see that Grafs has Accurate 2200 1-pounders available.

Here is the new 25-223 Build.

16" barrel med contour mid length gas.

I may paint it later, but want to break it in first.

http://i859.photobucket.com/albums/ab156/djsteeber/1c203071-3e47-404d-aa59-55f3ef4b90d7_zpse521eedb.jpg
http://i859.photobucket.com/albums/ab156/djsteeber/f28014cf-8206-4c0f-86f7-33ed4cd8b5ec_zpsc074d1e3.jpg

Nice smoke pole.  I have always like the  Free-Float Dissipator set-up on the AR.  The rifle length fore arm give you more options when you are looking for a "rest" point on your rifle.

Please pardon my ignorance but how does his cartridge compare to the 6.8?
Also wouldn't a carbine length gas system provide more flexablity load wise for a greater range of bullet weights.
But answering my own question, how many .25 cal bullet weights are available?
Not like the .458.

Here is a post from a long time back. I think page 17.  You willl have to go back and see who the author was.
Might help a little. Posted on 2/1/2011:



"Okay, guys, I took the liberty of comparing the .25-223 to a variety of similar cartridges both in terms of energy delivered at the muzzle and then at 200 yards:



5.56 M193 – 55 grain FMJ – 3165 fps / 1223 ft lbs at muzzle; 2451 fps / 734 ft lbs at 200 yards

5.56 M855 – 62 grain FMJ – 2938 fps / 1188 ft lbs at muzzle; 2309 fps / 734 ft lbs at 200 yards

223 TAP FPD – 75 grain BTHP – 2528 fps / 1064 ft lbs at muzzle; 2044 fps / 696 ft lbs at 200 yards; 32.4" drop at 400 yards

5.56 TAP T2 – 75 grain BTHP – 2713 fps / 1226 ft lbs at muzzle; 2208 fps / 812 ft lbs at 200 yards

7.62x39 - 123 grain FMJ - 2245 fps / 1377 ft lbs at muzzle; 1637 fps / 732 ft lbs at 200 yards

7.62x39 - 154 grain SP - 2097 fps / 1504 ft lbs at muzzle; 1654 fps / 936 ft lbs at 200 yards

25-223 - 100 grain SP - 2540 fps / 1432 ft lbs at muzzle; 2041 fps / 925 ft lbs at 200 yards; 32.6" drop at 400 yards

6.8 SPC – 90 grain HP - 2870 fps / 1646 ft lbs at muzzle; 2017 fps/ 813 ft lbs at 200 yards

6.8 SPC – 115 grain FMJ - 2400 fps / 1471 ft lbs at muzzle; 1859 fps/ 882 ft lbs at 200 yards

6.8 SPC TAP - 110 grain BTHP - 2570 fps / 1613 ft lbs at muzzle; 2106 fps/ 1083 ft lbs at 200 yards; 30.4" drop at 400 yards

300 BLK - 123 grain FMJ - 2315 fps / 1462 ft lbs at muzzle; 1729 fps / 816 ft lbs at 200 yards; 46.7" drop at 400 yards

30-30 Win – 150 grain SP - 2270 fps / 1716 ft lbs at muzzle; 1705 fps / 968 ft lbs at 200 yards


Notes/Takeaways -

I used data from 16"-18" barrels for all cartridges, which explains why the velocities shown above for certain cartridges (the 5.56 service loads, for example) are slightly lower than the usual published velocities.

The 25-223 gives a meaningful increase in delivered energy over even the hottest .223/5.56 loads at all ranges.

The 25-223 holds its own extremely well against the 6.8 SPC, especially at range. At worst the 25-223 gives up 10-15% in terms of energy. At best the 25-223 is equivalent or slightly better in terms of external ballistics.

No meaningful difference in trajectories at 400 yards between standard loadings of the .223/5.56, 25-223, and 6.8 SPC.

The 25-223 gives up basically nothing to supersonic 300 BLK loadings, and offers clear advantage at range. "

Willz, just to add to possum's post, I have done 2700-2750 with a 100gr in two rifles, both with 20" barrels. So that really gets this cartridge closer to the 6.8 territory.

The .25-223 will not beat a properly spec'd and loaded 6.8 SPC in raw power.   If you are looking for max energy and velocity the 6.8 is a better choice.

Having said that, the .25-223 offers performance that is reasonably close while maintaining the use of standard bolts and magazines and making use of cheap and plentiful .223 parent brass.  It is the easiest wildcat I've had experience with in the AR platform requiring no fire forming or excessive brass trimming and offers a 20-30% increase in energy and momentum over similar .223 loads in a 16" barrel.  It works well with most bullets in the 75-100gr range and lends itself well to use as a light handy rifle capable of taking small to medium game.  If that's what you are looking for, I would recommend it.

I also believe it has quite a bit of potential as a tactical rifle but I would hesitate to recommend it for such use as very little data on modern .257 caliber projectiles used against human targets is currently available.

Hello all,

I recently received my new barrel from 320pf and have assembled my new upper.  The barrel is a 20 inch light profile, being .790 under the handguard and .630 in front of the gas block.  It has a rifle length gas system and has been assembled using a Rock River lower and upper.  

I have converted some LC ’07 brass using the Redding bushing style system (works great) and trimmed to 1.7 inches.  Primers used are CCI Small Rifle # 400 (I know these aren’t ideal in the AR system but I have several thousand on hand and never had any issues in the .223 upper).

Here is some data that I was able to get this past weekend, temp was around 80* and elevation is around 2400 feet.

87 gr Speer HP TNT seated to 2.25” OAL
23 gr Benchmark
2351fps
2393
2351
2393
2415
Avg-2380
ES- 64
SD- 28
Perfect function, slight bolt face swipes on case head
5 shot group 1.73” with the first 3 being in the same hole

87 gr Speer HP TNT seated to 2.25” OAL
24 gr 2230
2501fps
2501
2492
2520
2492
Avg-2501
ES- 28
SD- 11
Perfect function, slight bolt face swipes on 4/5 cases
First 4 shots in .33”, last round stretched it to .9” (I got excited and pulled it)

100 gr Speer SP Hot-Cor seated to 2.25” OAL
23 gr 2200
2549 fps
2501
2530
2554
2549
Avg- 2536
ES- 53
SD- 21
Failure to feed next round 4/5, moderate to strong bolt face swipes...too hot
Overall group around 1”

100 gr Speer SP Hot-Cor seated to 2.25” OAL
23.5 gr Benchmark
2385 fps
2376
2355
2380
2389
Avg- 2377
ES- 34
SD- 13
Perfect function, slight bolt face swipes
Overall group of 1”

85 gr Nosler Ballistic Tip seated to 2.25” OAL
23 gr Benchmark
2424 fps
2419
2406
2424
2428
Avg- 2420
ES- 22
SD- 8
perfect function, very slight bolt face swipes
First 4 rounds into .5”, last round stretched it to 1.3” (again that was my fault)

85 gr Nosler Ballistic Tip seated to 2.24” OAL
23 gr 2200
2661 fps
2666
2629
2656
2672
Avg- 2652
ES- 43
SD- 16
Failure to feed next round 4/5, moderate to heavy bolt face swipes, slightly flattened primers
Overall group size was 2.3”

I learned a lot this weekend about this system.  It is very soft shooting, more-so than I thought and I believe the rifle-length gas system has a large part in that.  I also am very pleased with what I see to be the accuracy potential for this cartridge and barrel.  When I get my suppressor I think this will be a great predator/varmint/medium game tool.  

I was surprised with the overall consistency in speeds with low ES and SD for all of the loads.  I believe this plays a huge part in the accuracy of the system.  I am excited to continue on load development to see just how accurate we can get.

On the downside, I am kinda bummed about the velocities that I am getting.  I was hoping for closer to 2800 or slightly above with the 85-87 gr bullets.  I know that Reloader 7 has proven to be good with this cartridge, but I have been trying to find some locally since June without luck.  I will keep working on loads and sharing the results as I go along.  If you have any suggestions or input please feel free to share, I am always happy to take constructive feedback.  Hope this is educational for some of you.

I was able to get over 2700fps using the 87gr HotCor and just shy of 2900fps with a 75gr V-Max in my 16" using H4198 if that is available in your area.  I could only get to 2600 with the 85gr Nosler BT due to the longer bullet and case encroachment.  I was also able to reduce ejector swipes by going with a heavier buffer.

What barrel length are you using? I'm assuming 20" since you are using a rifle gas.

Thanks for the info.  Yes it is a 20" barrel, I edited my post.  I have not seen any H4198 anywhere either so I will keep my eyes open.  Do you have a recommendation for a heavier buffer, I am using the one that came with the Rock River rifle which was the 18" HBAR with rifle length gas system.  Will a new buffer affect function with my .223 upper?  Thanks!

Inquiring minds want to know.

Does your stock use a rifle buffer or carbine buffer? If it uses a rifle buffer and spring it will already be a heavy buffer, if it uses a carbine buffer it probably uses a standard weight buffer and going up to an H2 or H3 may reduce ejector swipes.  

Buffer weight is a tuning measure and increasing buffer weight can smooth things out and improve reliability or it can cause cycling issues depending on your particular rifle so it is hard to say if it will work with the .223 upper without trying it. Generally if the rifle is under gassed it can cause issues and if it is over gassed it can help. Most factory uppers are a bit over gassed to ensure reliable function and a bump up in buffer weight works out pretty well. Most of my .223 guns prefer an H or H2 buffer.

I am building two 12.5-inch and two 14.5-inch barrels as we speak.

Based on some QL modeling, I would guess that a 12.5-inch barrel would push a  75 g bullets to about 2800-2850 fps; 87 g bullets to about 2600-2650 fps; and  100 g bullet to about 2400-2450fps;

Just for reference, the Hodgdon Reloading Data Manual No. 27, lists 75 g bullets at ~2800 fps,  85 and 90 g bullets at ~2600+ fps;  and 100 g bullets at ~2450+ fps for the 6 mm  TCU.  So I think that the QL model data will be close to real world results.

I hope this answers your questions.

320pf

Hi  rdc_bones,

The fact that your rifle functioned/cycled better with A2230 and Benchmark suggests that your setup likes the slower powders. A2230 and Benchmark have similar burn rates which are slower than A2200. This suggests that your upper is slightly over gassed.

Your barrel, however, is still pretty new and is probably not seasoned yet, so things may change a bit still. I agree with Altair, you want to check your buffer weight. You might also want to check your spring.

Your Rock River rifle was designed for an 18" HBAR with a rifle-length gas system.  This set up has about 5-inch of dwell time (the distance between the gas port and muzzle) instead of the standard 7-inches. So basically, the gas pulse to work the action is about 28-30% shorter. So RR probably lightened your spring and buffer so the 18-inch barrel would run more reliably.  

When you get your suppressor the gas pulse will be somewhat longer (more gas) than without the suppressor. So if you are over gassed know it will more obvious with the suppressor.

Don't panic yet, increasing the buffer and spring weight will help a slightly over gassed gun and you can always go with an adjustable gas block if the heavy spring and buffer do not fix the problem.

Based on the experience of other 25-223AR shooters, you should be able to get the velocities that you are looking for, once you get the gas system worked out.

Give me a call if you have any questions.

So I have just reloaded my first 5 bullets.

I am going with Reloader 7, CCI #41 primers, and Nosler BT 87g
I am working my way up from 22.0g to 24.0g.
I loaded the first 5 with 23.5g (mainly because that is how the first powder measure worked out).

With 23.5g, the case looked full, but the powder was still below the neck.
I seated the bullet so that the OAL was 2.72 (ish).  I measured it in the case gauge and all looks fine.

My questions?

Will the powder be compressed, since the bulled was seated quite a bit into the case?
I did hear some crunching in the last few 0.1 of the case seating.
Has anyone else had any experience with this?

Thanks.

http://i859.photobucket.com/albums/ab156/djsteeber/20130905_223738_zpsec8f7bde.jpg

Also, I believe the Nosler I have is 1" oal.  Might be too long.

I have a couple questions.  First, if you are working up a load from 22.0gr of powder to 24.0gr of powder why start at 23.5gr?  I would not consider that to be a safe practice.  Each rifle is a bit different and there is no published load data for this round so starting conservatively and working up slow is the only way to do this safely.  The only reason you give is something about the powder measure "working out that way".  I don't know what that means except to think that is just where it landed the first time around, which is not how you decide where to start.  I'm not trying to break your balls, but I don't want to see you do something unsafe.

Second, you said you were using an 87gr Nosler BT and the OAL was 2.72".  Did you mean an 85gr Nosler BT and an OAL of 2.27"?  I'm not aware of an 87gr NBT in .257" and an overall length of 2.72" will not load in an AR mag or chamber in a .25-223 chamber.  Again, not trying to bust balls but if asking for advice getting the details correct is important as a .4" difference in loaded length is extremely significant.

As for compression of powder, yes it can happen with this cartridge.  It doesn't necessarily mean the load won't work but I would never start with a compressed load.  If you get powder compression on the first load you try with a given powder and bullet you are starting too high IMO (see warning above).

Altair, agreed, I am probably moving too fast, and need to slow down.

My plan was to make 5 rounds each (22,22.5 ... 24.0) and take them to the range.
The observations I had were on the 23.5g of REL7 which I loaded first.  The plan is not to shoot these first.
Since my range is a few miles away, I wanted to have a full set to try out, even if I needed to disassemble them if not safe.  In hind sight, probably a bad practice.

BTW, if I am not safe, I want my balls broken.  Better by people that know than by a malfunction.

As for OAL, I believe you are correct, simply because a 1.7" case and a 1" bullet, cannot be 2.72".  My dyslexia is kicking in.
I do have everything written down in a note book, but tried to write this from memory.

I am super glad you confirmed my worries about a compressed load.  I actually think I will be more conservative and work from 20g up.

Thanks for your  comments.

I've been away from this thread from a long time, but wanted to report that the .25-223 has been dealing out straight death to pigs.

The .25-223, 24.0 grains of R7, and the 80-grain Barnes TTSX is a guaranteed one-shot kill. Period. With the many pigs now killed with this combo , I cannot see how a .30-06 or similar could have done any better.

The latest:

I haven't used RE7 with the 85gr Nosler but I have used it with the 80gr TTSX.  Both are long bullets with similar weight so I would expect the powder charge to be in the ballpark.  I hit my max load at 24.0gr with the 80gr TTSX so starting the 85gr NBT at 22.0gr would probably be ok, but if it were me I'd try 21.0gr first just to be safe as the Nosler is heavier and perhaps slightly longer.

If you were loading several sets of five rounds stepped at 0.5gr ahead of time due to having a decent drive to the range there is nothing wrong with that.  From your post I got the impression that you planned to start at 22.0gr and just happened to load 23.5gr and were going to try that before shooting anything with less powder, which is what caused my concern.  If you load a string of several sets of five rounds and shoot them in order from lowest charge up you should be fine.  If you find your max load before shooting the whole string just stop moving up and break down those you loaded with more powder, which is what it sounds like you were planning to do.  Obviously if you do something like that just make sure the rounds with different charges are in separate well marked containers so you don't have any accidents.

Welcome to the .25-223, it is a surprisingly capable round for its size (see Wombat's post above).

Have you recovered any bullets or do you generally get pass throughs?  If you have I'd love to see them.

All have completely penetrated - even when the pig is shot basically end-to-end.

After now seeing dozens of game animals killed with lead-free bullets (almost all Barnes TSX or TTSX) I believe they provide definite advantages for intermediate cartridges like the .25-223, but any advantage is basically erased (for shooting light-skinned North American game animals like pigs or deer) for the larger .308/.30-06 class cartridges. They are definitely penetrators.

Arrow422, your COAL can't exceed 2.26.  Unfortunately we are restricted by magazine length.  However, PRI mags allow seating out 2.30 so I will picking them up to try.

I have loaded the 85gr BT with 24.0 of Re7, but every gun is different.  For me its safe, but for you who knows....  You can start to experiment with heavy buffers and springs too.

Chewbacca,

Thanks, I re-measured the OAL, and I am sitting at 2.266.  These fit in the Lancer mags I have.
I made up a few test rounds.  (no primer, no powder) and did a function test with the mags and the chamber.
A-OK.

I would be interested to hear how the PRI mags work

I was able to get back to the bench, and now have 5 rounds in each (21.0g - 23.5g) at 0.5g increments.

I do have an adjustable gas block on the rifle.  I may play with the buffer tube if it becomes necessary.

My goals with these first set of rounds, is to safely season the barrel.  Once I have about 50 rounds down range, I'll work on fine tuning the accuracy.
Since this will be my deep woods (under 100 yard) rifle, I am realistically looking for a sub 3" group with a EOTech site.

Sub 100 yards!?  Load up some 117 Hornady RN.

I'm surprised you are getting the length with the Lancer.  My Lancer is shorter than my Pmag... At least I think (will go check now).

I drilled out my gas port and will be adding an adj gas block with a low mass carrier.  I plan to tune it to just allow enough gas to cycle, allowing the bolt to stay locked slightly longer and hopefully allowing higher safe pressures and therefore more velocity (albeit slight).  Its all in good fun right!

Once I rebuild my rifle, my goal is to use the 120 speer grand slam (bullet length of 1.088) with the PRI mag and try to achieve 2300 fps.  That would essentially give 762x39/300 BLK ballistics with a higher BC and SD.

No deer yet, but working on the yotes. This one came to a deer grunt call on the run.  Complete pass through with hornady 100gr/aa2200.

http://i313.photobucket.com/albums/ll373/scpossum1/image-2.jpg

Nice yote.  Was it a DRT or did the yote run a bit? From the photo I would think it was a DRT.

He was close when  I shot him. He traveled about 40 yds before he piled up. Been deer hunting three times and shot two yotes in the past week. We have a real problem down here.

So I'm really curious about this cartridge, almost bough a barrel kit from 320, but passed last minute, have questions still.

Setting a max psi of 58,000, what kind of max charge velocities are we seeing with this with what weight bullets?  I'm sorry if it's been posted already a bunch of times but we're at like 65 pages which makes it hard to pluck all the info.

Is there a chart or something I missed?  Definitely looks interesting.

For a rough idea, from a 16" barrel we've seen velocities in the ballpark of

Bullet..........Velocity
75gr............2850-2950fps
85gr............2700-2800fps
100gr..........2500-2600fps

IIRC you can add about 150fps for a 20" barrel.  Also remember that long for weight bullets, like the Nosler Ballistic Tip, will clock slower than others in their weight class because the case is small and encroaching on case capacity affects velocity more than in larger cartridges.  Also remember that these velocities aren't at tested pressures.  As far as I know there has not been any actual lab testing for pressure with this cartridge.  These numbers are from reading pressure signs on cases, which isn't an exact science.

I hope this helps.

Correct me if I'm wrong but wouldn't something a bit smaller and faster in the 75-87gr range be a bit better for coyotes?  Obviously the bullet did its job, I just thought people typically used something closer to a varmint bullet for coyotes.

Or is it that you are deer hunting and using 100gr bullets and just happen to have shots at coyotes?

You are correct. Faster and smaller would be better for coyotes. I am deer hunting and we keep crossing paths. This one came to a grunt call set to a higher pitch than I normally use.  Two minutes after the call i heard him "loping" through the pine straw. You know, that kind of bouncing gate as they run. We have a real problem with them and the unwritten rule on our place is to take the shot when they appear no matter what you are hunting for. We were dove hunting earlier in the day around bean fields and they flushed one out. He got peppered pretty good before he got out of the dove field.  

Double tapped

Hi TheHomelandSoldier,

Altair's response is pretty much right on.  I may add however, that internal ballistic modeling solfware (QL and Powley) that predict velocity and pressure for a given powder charge and bullet weight match the velocity numbers pretty well. For example, I was just working up some loads for IMR4198 and 75g Hornaday VMAX out of my 16.5 in barrel. The modeling software predicts 21g of 4198 should produce 2600fps @ 45000 psi. The real load data for 21.1 grains of 4198 in my barrel is 2617 fps. So I think that the estimated/modeled pressure  (45000 psi) is pretty close (I would guess within about 3000 psi).

Here are my results for IMR4198 and 75g Hornaday VMAX bullets.

IMR4198 and 75g Hornaday VMAX bullets 16.6-inch barrel

Load (g) Velocity (fps) Estimated Pressure (psi/CUP)

21        2617          45000/40400

21.5      2680          49000/42900

22        2700          50000/43700

22.5      2721          51000/44400

23        2777          54000/46400 Very consistent shot to shot velocities

23.5      2846          57000/48800

24        2892          60000/50500 Near Max Load based on pressure model

24.5      2966          64000/53300 Over Max Load  based on pressure model. Very consistent shot to shot velocities

25        2999          67000/54600 Slight swipes on case head Over Max Load

Standard Disclaimer: These loads are safe in my rifle only. Use these loads as a guideline and work up slowly.

The shot to shot velocity deviation for all of these loads was 10 to 30 fps and the whole string grouped about 1 inch at 100yrds. This combination is now my goto varmint load.

I have added some more velocity information to Altair's list (below) for the heavier bullets that have been tried and the Barnes 80 gr TTSX bullet.

Bullet..........Velocity
75gr............2850-2950fps
80gr............2770-2830fps Barnes TTSX This is a long (~1.01 inches) bullet.
85gr............2700-2800fps
100gr..........2500-2600fps
110gr..........2350-2400fps (Nosler AccuBond) Very long bullet for caliber.
117gr..........2300-2350fps Sierra GK
117gr..........2350-2400fps Hornaday RN

Thank you that is very helpful!

320pf

Thanks for the info on the IMR4198.

The FE truck just dropped off some AA2200  

That should make you Happy, Happy, Happy.  It would for me.

So, I need a little (or maybe big) advice.  I took the rifle out to the range today.  Here were my observations.

First of all I shot 5 rounds a piece 21.0 - 23.5 g REL 7, 85g Nosler BT.  No signs of over pressure on any of them.  

On all rounds, I was unable to get the BCG to lock back on an empty mag.

With the 23.5g, I backed out the syrac adjustable gas block after each shot.  I believe it is out all of the way.
I was getting partial ejection.  My assumption is under-gassed.

Also, when loading a round, the BCG does not always want to go forward fully.  
I can pound on the forward assist to get it to move, and in some cases, can just break a part the rifle and push the BCG forward.

Now, the rifle only has 30 rounds through it.

From the lack of pressure signs and reading other posts, I feel comfortable going up to 24g of REL.

My questions:

Has anyone had similar experience?
What should I check?  lighter buffer tube?

BTW, once the shell is set, it shoots exactly where I am aiming.  I love the round, just need some advice to make my setup great.
If there is more info that is needed, let me know.  (like weight of buffer tube, manufacturer, etc)

One final observation, the 10 round PMags are shorter than my Lancer M5s, (i.e. my bullets that measure 2.266 need to be shortened just a bit for the pmags)

Thanks

This part sounds like the brass is not being sized correctly. Did you get a chamber guage with the barrel?  And do the rounds seat fully in it?  I had that same problem with a different AR and the dies were not sizing the body of the brass correctly. Also had that problem with certain headstamps of brass in that same rifle not sizing correctly. What about extracting the round after it is fully seated?  Is it hard to extract?

I am assuming that the bcg fully seats all the time when a round is not chambered.

Agreed, sounds like the body isn't getting sized properly or the case shoulder isn't quite getting pushed back far enough to me. It could also be trim length.

Will sized unloaded brass chamber properly?