[mavericks]

Results from load testing at the range yesterday. 61 degrees, 8-10 mph wind gusts northwest. Improvements in loading process from last time were backing out seater die from holder and loading to 2.280".

I'm going to try tubbs final finish and using some copper solvent to see if it will help with the flyers. These are my first good set of handloads so there is promise. Also first time using the geiselle trigger. Very easy on the finger and fun to use.

LWRC 14.5" 6.8 SPC M6A2 on Harris bi-pod, geiselle service hi speed, leupold LRT 8.5-25x, h2 buffer, Tubbs flat spring

200 rounds made with Lee turret, Lee dies, RCBS Loadmaster:
Speer TNT 90 gr with H322 (29,29.5*,30,30.5,31) & H4198 (26,26.5,27,27.5*,28) - 10 shots/load
Sierra Matchking HBPT 115 gr with H322 (26,26.5,27,27.5*,28) - 10 shots/load
Remington FMJ 115 gr with H322 (27.5,27.8*,28,28.2,28.5) - 10 shots/load

CCI #41 primers, new SSA brass

Winners were:
________________

Speer 90gr TNT w/ 29.5 Grains of H322
Velocity Variance Coefficient 1.3%
SD 34.9 ft/s
Avg Vel 2613.9 ft/s
Group 1" w/ 3 flyers
________________

Speer 90gr TNT w/ 27.5 grains of H4198
Velocity Variance Coefficient .3%
SD 8.2 ft/s
Avg Vel 2767.2 ft/s
Group 1.5" w/ 1 flyer
________________

Sierra 115gr HBPT w/ 27.5 grains of H322
Velocity Variance Coefficient .6%
SD 15.4 ft/s
Avg Vel 2446.8 ft/s
Group 1.8" w/ 1 flyer
________________

Remington 115 FMJ w/ 27.8 grains of H322
Velocity Variance Coefficient .8%
SD 18.9 ft/s
Avg Vel 2454.1 ft/s
Group 2" w/ 3 flyers
_________________

 

[marinesg1012]

Was that at 100?

 

[mavericks]

Was that at 100?

Oh yeah. lol forgot that metric. Yep 100yd

 

[marinesg1012]

Looks good, how many rounds do you have through the rifle?

 

[mavericks]

Looks good, how many rounds do you have through the rifle?

Thx, 700 now. Bought it in 10/08 used from a guy that said it had only 200 rds thru it. I believe I've put 300 rounds through it prior to the range test yesterday.

The speer tnt 90gr in h4198 seems to have 100 ft/s more velocity than the similarly accurate h322 load. I'll test it out alittle more this weekend and make use of the lead sled instead of bipod maybe.

One other takeaway i failed to mention was that the speer tnt h4198 batch utilized brand new ssa brass which I fully resized. The rest of the load combos did not go through the sizer fully but just slightly enough so that the mouths were uniform.

 

[marinesg1012]

Sounds good.

 

[paulosantos]

Looks good, how many rounds do you have through the rifle?

Thx, 700 now. Bought it in 10/08 used from a guy that said it had only 200 rds thru it. I believe I've put 300 rounds through it prior to the range test yesterday.

The speer tnt 90gr in h4198 seems to have 100 ft/s more velocity than the similarly accurate h322 load. I'll test it out alittle more this weekend and make use of the lead sled instead of bipod maybe.

28.6 Gr. of H4198 and the 90 Gr. bullets seems to be the sweet spot. I'd load some up with 28.6 Gr. and try them also. Matter of fact, from a 14.5" barrel, H4198 would be my first choice of powder. H322 is too slow in a short barrel, especially with the 90 Gr. bullets. H322 is OK for the heavier bullets out of the 14.5" barrel, but the H4198 can keep up with it.

 

[Test_User]

H4198 IMR4198 Rel 7NMorma 200 all give very good groups with the 90s up to the 110s

 

[mavericks]

28.6 Gr. of H4198 and the 90 Gr. bullets seems to be the sweet spot. I'd load some up with 28.6 Gr. and try them also. Matter of fact, from a 14.5" barrel, H4198 would be my first choice of powder. H322 is too slow in a short barrel, especially with the 90 Gr. bullets. H322 is OK for the heavier bullets out of the 14.5" barrel, but the H4198 can keep up with it.

Yeah I can try it. The lee load die instructions have a max load of 28gr for h4198 though. Hey, I just took a pic of the brass that came from the H4198 batch. They are in order of load increments. From bottom to top, lowest to highest increments. Have always seemed to have those half crescent marks and the primers seem to be ok even at 28gr. But was wondering if you guys see anything to be alarmed about from the picture.

 

[paulosantos]

Brass looks good.

 

[mavericks]

sweet

 

[RUTGERS95]

That's some nice shooting!!!!!

 

[ron169]

Do you have a link where those targets can be downloaded>?

 

[BLACK LION]

I am envious of your re-loading abilities....

 

[dough]

Do you have a link where those targets can be downloaded>?

http://www.6mmbr.com/targets.html

 

[mavericks]

That's some nice shooting!!!!!

thx, guys. I was actually a little hesitant about posting the groups because my .22LR upper and .22/.25 airguns puts these to shame with ~.25 moa @ 100 and zero flyers.

 

[Test_User]

Guys there are some serious swipes on some of those cases. They are not all Ok. There are also extractor bends on the rims.

Starting at the top left to right
row 1
1 swipe at 9
2 swipe at 5:30
3 swipe at 2
4 extractor bend 11
5 clean
6 bad swipe 11

row 2
1 bur metal filing raised at 12 from swipe being knock off
2 swipe at 3 bend at 9
3 light swipe 11
4 swipe 10 bend 4
5 bad swipe 9
6 swipe 9:30

row 3
1 OK
2 swipe 6
3 good
4 light swipe 3:30
5 good
This would be a max load but careful when it gets hot.

Row 4
a couple with light swipes but in general Ok as above but should check with rapid fire and recheck in summer temps

Row 5

3 looks dif pressure than the rest. It has a swipe at 10 and the prime looks flatter than the rest maybe a dif load or case got mixed up? All the rest look good.


Not trying to be a kill joy but I also want your cases to last along with your bolt. 27 is where you should have stopped and then dropped back .5 to find your accuracy load. 27.5 and 28 are too hot and when you rapid fire and or temps go up you will have issues.

If you have a caliper measure the case head expansion line on a few from each group and I bet you will see it drop as the load goes down. Number 6 non row one is the worst the primer is the flattest and it has a deep swipe at 11:30 Everyone of the top row looks over except which is probably the angle and glare.


Now I know Rcrandall had swipes on one of his older guns even with loads he knew was OK.

Is this one of the newer LWRC with hammer forged barrels? Could it possibly be one of the old SAAMI chambered ones or one of the SPCII that had that line of chrome at the case neck in the chamber? If so a DMR or SPCII reamer will fix that.

 

[mavericks]

Guys there are some serious swipes on some of those cases. They are not all Ok. There are also extractor bends on the rims.
...
If you have a caliper measure the case head expansion line on a few from each group and I bet you will see it drop as the load goes down. Number 6 non row one is the worst the primer is the flattest and it has a deep swipe at 11:30 Everyone of the top row looks over except which is probably the angle and glare.

Now I know Rcrandall had swipes on one of his older guns even with loads he knew was OK.

Is this one of the newer LWRC with hammer forged barrels? Could it possibly be one of the old SAAMI chambered ones or one of the SPCII that had that line of chrome at the case neck in the chamber? If so a DMR or SPCII reamer will fix that.

I bought this used from someone on arf back in october. They said there was 200 rnds thru it so i assumed it was a 2008 model. It says M6A2 6.8 on it. I will call LWRC and ask them about the specs using the serial number. It looks to me like the swipes keep happening even on lesser loads such as 26gr of h4198 on speer tnt 90gr. The swipes (half moons) would also occur on factory SSA pro-hunter rounds in both regular and tactical loads as well. I'll check the case head expansion...too bad I dumped all the brass into one bin today. lol.

What makes the swipes? Is that part of the extractor being pressed into the case?

 

[Test_User]

It is the ejector hole. The case head actually flows into that hole. The bad ones are when it flows into the hole and then upon ejection as the case is rotated the raised flow is cut off and will sometimes leave a bur as I noted on one of them. With what you are saying about all cases showing this. As I noted this is similar to what RCrandall had experienced. When we did the barrel perf testing last summer we also did a few other experiments that I did not put into the report as to do so in to the level it could be fully explained would have taken forever and without woudl have left people confused. We did testing into what changes and specs could effect the pressure indication on a case. I contacted a person that did very very advanced modeling of what happened with a case bolt chamber when a round is fired. Based on various things discussed I tried various things. To not make this a 10 page post chamber wall to case friction, headspace ( distance between case head and bolt face with round seated forward into the chamber shoulder), chamber size in relation to case size near the rear of the case body and chamber all can effect swipes. Just as it is normally firing pin hole effects primer dent and piercing as much as pressure and primer cup hardness. Can you have your headspace checked? OR do you have a Hrdy headspace guage? You could measure the case length compared to what others are getting.

SSA sizes there cases to absolute min in all dimensions including headspace. DO you have your FL sizing die setup per the instruction that came with it ie screw down until it touches the seat then another 1/4 turn type setup? This sets case sizing to give maximum headspace. Setting the shoulder back the max. Ideal shoulder setback or created headspace is .003-.004 for an AR. If so and you do not already have one I suggest getting the Hornady headspace guage and setting the shoulder back .003 from the reading you get off a fired case. It will increase your case life and likely your accuracy yet still give you plenty to allow reliable feeding.

In the end if you are getting swipes no matter and you are still getting 10 reloadings from your cases without primer pocket issues then your pressure is likely not a issue. I would suggest then you move to the CCI BR4 or the Rem 7 1/2 as their primers cups may tend to be a tad softer than #41s used by SSA and mil or WOlf 5.56 primers so you can hopefully see the flattening and use this as a rough guide to know if you are getting to hot by chance. Next time when you are priming those cases see if you feel a noticeable dif in primer seating of differnt cases. Some being very firm and others going in with almost no pressure. If so then you know you have rounds that were certainly hot or possibly to much headspace.

The biggest thing to being able to use visual signs like this is to do everything as consistent as possible to limit other things effecting it. Use same brand cases, size them the to the same setback, use the same primers, same neck tension etc..

Like I said was not trying to be an alarmist or being nit picky but with my ARs with what we have seen correlation between swipes and pressure those cases look like they had experienced high pressure. You had asked if the cases looked OK and based on this they did not. If there is some other reason for it other than pressure OK. Based on your pictures they are showing increased swipe depth and severity as your loads go up so there is a correlation of some sort IMO.

 

[mavericks]

Just posted this while you were writing the last post. So i haven't read it yet.

I took 3 hi-res pictures of the chamber. I'm not sure what to look for with the chrome if it is there. Everything look silver colored. To check if it is SPCII by hand, can I take a wire/caliper and measure the length from the barrel start to the edge closest to the extractor? Should it be a certain length and 0.005 longer than whatever the SAAMI spec length is? Lemme know if i'm totally off.

http://www.unidatum.org/lwrc/chamber/IMGA1087.JPG
http://www.unidatum.org/lwrc/chamber/IMGA1091.JPG
http://www.unidatum.org/lwrc/chamber/IMGA1092.JPG