6.5x55 reloading help

[Rob404]

Got to the range and the aforementioned experiments lead to two discoveries: first that at .01 off the lands this rifle is sub MOA. The difference in accuracy between .04, .02 and .01 is amazing. Second discovery occured when a range officer took a look at what was going on. His opinion is that it is not a pressure issue. He believes it is a problem with the firing pin. We were joined by another range officer who agreed. I got some advice about ajusting a mauser bolt. So, all in all, and eventful trip to the range!

I did mention possible Firing Pin problems in previous posts I.m glad the range officers concur, so what OAL did you finally come up with

 

[Pheroze]

Rob44, I was thinking about your intuitive insight into the problem when they were chatting with me! Very Cool. Now, I have not fixed it yet so stay tuned. The thinking is that the firing pin is either too sharp, long or dirty.o Apparently we can adjust the mauser action so once I go back to Google university I will take a crack at that.

OAL 3.209.

 

[Pheroze]

Rob44, I was thinking about your intuitive insight into the problem when they were chatting with me! Very Cool. Now, I have not fixed it yet so stay tuned. The thinking is that the firing pin is either too sharp, long or dirty.o Apparently we can adjust the mauser action so once I go back to Google university I will take a crack at that.

OAL 3.209.

 

[Rob404]

Rob44, I was thinking about your intuitive insight into the problem when they were chatting with me! Very Cool. Now, I have not fixed it yet so stay tuned. The thinking is that the firing pin is either too sharp, long or dirty.o Apparently we can adjust the mauser action so once I go back to Google university I will take a crack at that.

OAL 3.209.

There could be a little metal shaving in the bolt assembly while Zavasta's are sturdy as hell some sometimes their assembly leaves a little to be desired,you could try spaying it down with WD40 then blowing it out with compressed air, if not just pull it apart and clean it and look for a possible burr

 

[Pheroze]

I pulled the bolt apart and cleaned it. It did not have any noticeable burrs. There was a gritty dark lubricant which I cleaned off.

I heard from Woodleigh and they suggested switching to H1000.

Maybe I will do both. Have you tried H1000?

 

[Rob404]

Never tried H1000 mostly Winchester 748 and Reloader 22

 

[Pheroze]

The folks at Woodleigh are very helpful, that's for sure. I gave some more info about my rifle and this is the info I got:

Hi Pheroze,

An undersize firing pin can cause primer extrusion as per your photo, but it still takes a considerable amount of pressure to cause the primer cup to extrude.

Considering that you have a 20” barrel, you may get best velocity with 4350, but I would drop back 2 gr and see if you still get the extrusion effect.

Also, it is true that some primers are more prone to extruding. You could try Federal 210 with 40 gr 4350.


I have written to them again because I do not think the bullets are stabilizing. Where I got the shots to group, it is just a ragged hole. But the individual shots look more like pointed ovals. This situation just perplexes me. I have cleaned/lubricated the bolt and firing pin. However, I think I may start again with different primers.

Thanks again for the advice Rob44, it is much appreciated as I puzzle through this.

 

[Desperatezulu]

Apologies for making some rudimentary suggestions, but here goes:
1. You need to chrony the load. Until you know the speed, you're really flying blind. The only reliable indicator of pressure is velocity (unless you have super fancy pressure-testing equipment!). You're better off at this stage chrony-ing the load and not even worrying about grouping/hitting the target. Safety is first priority.
2. Measure the H2O capacity of your fired brass. This will give us a reference as to whether your S&B brass is thicker than normal brass (you did say the brass appears to be more robust than usual). If the brass is thicker than normal (i.e. the H2O capacity is lower than normal) then this would point to pressure spikes as the source of your bulged primers. For reference Lapua brass fired in my 6.5x55 on average holds 58.0 gr H2O.


Re the possible unstabilised bullets - what twist rate is your barrel? The 160gr bullets are pretty long and would need a 1:8 or 1:9 to stabilise properly. Velocity does also play a role in the stabilisation but much less than the tightness of twist.

 

[Pheroze]

Apologies for making some rudimentary suggestions, but here goes:
1. You need to chrony the load. Until you know the speed, you're really flying blind. The only reliable indicator of pressure is velocity (unless you have super fancy pressure-testing equipment!). You're better off at this stage chrony-ing the load and not even worrying about grouping/hitting the target. Safety is first priority.
2. Measure the H2O capacity of your fired brass. This will give us a reference as to whether your S&B brass is thicker than normal brass (you did say the brass appears to be more robust than usual). If the brass is thicker than normal (i.e. the H2O capacity is lower than normal) then this would point to pressure spikes as the source of your bulged primers. For reference Lapua brass fired in my 6.5x55 on average holds 58.0 gr H2O.


Re the possible unstabilised bullets - what twist rate is your barrel? The 160gr bullets are pretty long and would need a 1:8 or 1:9 to stabilise properly. Velocity does also play a role in the stabilisation but much less than the tightness of twist.

Thanks. "Rudimentary" pretty much sums up my experience so all advice is appreciated! Lol

I will take the chrono out next time. I have decided to load up a series of 160gr PPRN, 160gr RNSN and 140 gr partitions and see how they compare as I increase the powder. I did not go far with the RN SN before switching to PPSN but i do not recall any problems with stability or pressure. I am curious if the longer profile of the PPSN is adding to this problem. I will check H2O fill.

Again, thanks.

 

[Pheroze]

Re the possible unstabilised bullets - what twist rate is your barrel? The 160gr bullets are pretty long and would need a 1:8 or 1:9 to stabilise properly. Velocity does also play a role in the stabilisation but much less than the tightness of twist.

A quick internet search seems to indicate 230mm which I believe converts to 1:9.

 

[Pheroze]

Puzzling over this because, while the firing pin may be implicated, this just seems like a pressure issue. I also have the stability issue and that could also implicate the brass I think. I wonder if it is the brass. I took a look online and there are many folks reporting issues with the S&B brass - issues that sound like my primer issue, flash holes being too small or off centre and the brass being "too hard". Before doing anything else I am going to switch up that piece of the equation and see what happens. Freaking time is running out for my moose hunt so hopefully I can source some quickly.

 

[Rob404]

You didn't mention bullet destabilization before, and the barrel is pretty short, mine measures at 23", are you sure it's not stabilizing or perhaps the target is not solidly attached. I know this sounds stupid but it happened to me with an 8MM, the target looked like the bullet was going thru sideways, turns out it was the way I was attaching the target after I attached the target to a piece of cardboard then attached it to the backstop the problem disappeared,just a thought as sometimes it the simple thing we overlook I fhb e wind dies down tomorrow I head to the range with my 6.5 loaded with 160s and see what I chrono wit a longer barrel and we'll compare notes

 

[Pheroze]

Hi again Rob44

I only noticed the destabization this last time. The first time it was so windy I thought the target was just blowing around. I wrote to Woodleigh and this is part of the response:

There may be some pressure difference between the two bullets, but you are probably right about the short barrel not stabilizing the PP properly. The rn is 1.250” long, where as the pp is 1.381”, a considerable difference. The 160 pp stabilizes in most standard 6.5 x 55 and military rifles, but they generally have a longer barrel than your’s.

So, maybe several factors conspiring to challenge me!

"I get by with a little help from my friends"

 

[Rob404]

Hi again Rob44

I only noticed the destabization this last time. The first time it was so windy I thought the target was just blowing around. I wrote to Woodleigh and this is part of the response:

There may be some pressure difference between the two bullets, but you are probably right about the short barrel not stabilizing the PP properly. The rn is 1.250” long, where as the pp is 1.381”, a considerable difference. The 160 pp stabilizes in most standard 6.5 x 55 and military rifles, but they generally have a longer barrel than your’s.

So, maybe several factors conspiring to challenge me!

"I get by with a little help from my friends"

Yea I don't see how it would make a small hole one day and fly sideway the next, I'm not sure how long my barrel was before it was cut 26" 28" and it's a stepped barrel,but it was done by Ahlmans here in Minnesota and they have a fully staffed machine shop and been around a long time,

 

[Rob404]

I was loading some lighter weight bullets for my 6.5 today some 120s and 140s and ran into a problem using the common formula of 0 to .40 off the rifling, as it turned out there is barely enough bullet to crimp WTF. So back to google and the info I got was quite different than what I expected. The info I got goes against normal thinking. It seems that normal setback may leave to much room in the case and gives the powder to much room to expand before the bullet exits the brass hurting velocity and may not stabilize the bullet. So don't shoot me I'm only the Piano Player I just thought I'd pass along the info I found, Rob

 

[Pheroze]

I was loading some lighter weight bullets for my 6.5 today some 120s and 140s and ran into a problem using the common formula of 0 to .40 off the rifling, as it turned out there is barely enough bullet to crimp WTF. So back to google and the info I got was quite different than what I expected. The info I got goes against normal thinking. It seems that normal setback may leave to much room in the case and gives the powder to much room to expand before the bullet exits the brass hurting velocity and may not stabilize the bullet. So don't shoot me I'm only the Piano Player I just thought I'd pass along the info I found, Rob

Interesting. So back to basics? I will get new brass and load the 160 to the Max COL listed in the manual rather than any setback from the lands. I will see what happens and then adjust accordingly. What do you think?

 

[Rob404]

Interesting. So back to basics? I will get new brass and load the 160 to the Max COL listed in the manual rather than any setback from the lands. I will see what happens and then adjust accordingly. What do you think?

I did load some 160s and it appeared there was enough case to hold the bullet, But I think I'll load some deeper mabye 40-60th just to see what happens, it was when I got into the 120s 140s that I noticed there was barely enough to hold the bullet,thats when I went into search mode and found that info, I'm also going to buy a crimp today. We really need to get this problem put to bed,,have you been to the range and test fired your loads yet?

 

[Pheroze]

Not since I got the firing pin advice. I am waiting for new brass to arrive in the post. BTW, Lee had a min OAL of 3.000 for 160. Woodleigh do not have a suggestion.

 

[Rob404]

the 49th Lyman book shows 2.785 for a round nose bullet and 3.150 for a ballistic tip. Some say load it to the cameleer and forget it and more than a few articles I read say to use the 75/25 rule, measure the length of the bullet divide by 4 and use that amount as a bullet depth.
I load 13 different rifle loads plus 4 Pistol and this is the first time Iv'e had to do this much research. I'm going to work up some different depths for my 160s and Chrono them. Possible the 6.5 swede is a unique cartridge that just requires some extra tweaking to make it perform, a lot of this info I'm getting is from Canada and Europe

 

[Nicholas Barcomb]

The picture is not showing flattened primers or at least I don't see them in the picture. Is the bolt hard to lift or was the recoil to stiff? I don't use H4350 for my 6.5 x 55 SE, I use VV N550 for 85 to 129 gr bullets and VV N560 for 140 to 160 gr bullets. Primers LIE when trying to attribute them to pressures, there needs to be a few other factors involved. A tip from Ken Waters: Measure the pressure ring (the area approximately 1/8" up from the case head) on a freshly FL sized piece. Load it up and shoot it then measure the same spot (do this with the loads up to the supposed max, mark the cases). If the measurement is .001" to .003" it is "safe". If it measures .003" or over, back it off 1 gr. this will be the maximum load for your rifle. If there is a stiff bolt lift at anytime in the process, STOP!!!!!!!!!!!! I also load for a commercial 6.5 x 55 in a Tikka T3 Lite SS and these commercial throats are a bit shallower and tighter than the old military ones. Good luck and stay safe.