6.5 WSSM loads

[Poper]

I have mentioned my 6.5 WSSM in other threads.
Let it be known I enjoy the challenges of Wildcat load development if for no other reason than it forces me to think in a different fashion.

Currently, I have tried several different bullets in the 120g - 130g range and several different powders from 4064, 4350, 7828, 4831, 4451, 4166, RL15, RL17 and Vihta Vuori N540 & N550. I have been sticking to the light bullets because the COAL is limited by the length of the magazine. Longer bullets intrude on the case volume significantly. However, my efforts have been less than satisfying. 1-1/2" 5-round groups is the best I have been getting and 2"-3" and larger are the norm.

I have tried both Winchester and Hornady brass. Hornady has been more consistent and much better quality. Winchester's brass commonly has 10-20 percent folded wrinkles in the neck and shoulder and seems much more brittle compared to Hornady. Maybe just my imagination, tho. Regardless of the brass mfr, I turn the necks after forming, then proceed to complete the brass prep of uniforming primer pockets, deburring flash holes, trimming, chamfer and deburr case mouth.

I am always very wary about approaching what I would consider "maximum" loads for this little devil so I have been using .260 Remington load data as a starting point. Here is my rationale:
The maximum average pressure for the .243 WSSM (the parent case) is 65,000 PSI.
The maximum average pressure for the .260 Remington is 60,000 PSI.
Average case volume in grains of water for the .243 WSSM is 54 grains.
Average case volume in grains of water for the .260 Remington is 53 grains.
It is therefore reasonable to assume (in my estimation) that safe starting loads for the .260 Remington are a good starting point for the 6.5 WSSM. So far, that has created no problems for me and I have experienced no signs of excessive pressures. (No sticky bolt nor excessively flattened primers. No case head expansion of .001".)

So I have come to the conclusion that if I want to get better groups it will be necessary to use heavier bullets in the 140gr. - 160 gr. class.

The adventure continues, but if anyone on this board has any suggestions regarding this quest, I sure am willing to listen!

 

[Blue68f100]

What twist rate is your barrel?

 

[troy fairweather]

I have mentioned my 6.5 WSSM in other threads.
Let it be known I enjoy the challenges of Wildcat load development if for no other reason than it forces me to think in a different fashion.

Currently, I have tried several different bullets in the 120g - 130g range and several different powders from 4064, 4350, 7828, 4831, 4451, 4166, RL15, RL17 and Vihta Vuori N540 & N550. I have been sticking to the light bullets because the COAL is limited by the length of the magazine. Longer bullets intrude on the case volume significantly. However, my efforts have been less than satisfying. 1-1/2" 5-round groups is the best I have been getting and 2"-3" and larger are the norm.

I have tried both Winchester and Hornady brass. Hornady has been more consistent and much better quality. Winchester's brass commonly has 10-20 percent folded wrinkles in the neck and shoulder and seems much more brittle compared to Hornady. Maybe just my imagination, tho. Regardless of the brass mfr, I turn the necks after forming, then proceed to complete the brass prep of uniforming primer pockets, deburring flash holes, trimming, chamfer and deburr case mouth.

I am always very wary about approaching what I would consider "maximum" loads for this little devil so I have been using .260 Remington load data as a starting point. Here is my rationale:
The maximum average pressure for the .243 WSSM (the parent case) is 65,000 PSI.
The maximum average pressure for the .260 Remington is 60,000 PSI.
Average case volume in grains of water for the .243 WSSM is 54 grains.
Average case volume in grains of water for the .2460 Remington is 53 grains.
It is therefore reasonable to assume (in my estimation) that safe starting loads for the .260 Remington are a good starting point for the 6.6 WSSM. So far, that has created no problems for me and I have experience no signs of excessive pressures. (No sticky bolt or excessively flattened primers. No case head expansion of .001".)

So I have come to the conclusion that if I want to get better groups it will be necessary to use heavier bullets in the 140gr. - 160 gr. class.

The adventure continues, but if anyone on this board has any suggestions regarding this quest, I sure am willing to listen!

sounds like a nice cartridge im not a big 6.5 fan but i like the idea of this i a little browning or model 7. what rifle are u using. i have dreamed of makking a 35 wssm the the little guns. i seen some where they had the wssm brass for under a buck.

 

[Poper]

What twist rate is your barrel?

The twist rate on this barrel is 1:8.5.

 

[Poper]

sounds like a nice cartridge im not a big 6.5 fan but i like the idea of this i a little browning or model 7. what rifle are u using. i have dreamed of makking a 35 wssm the the little guns. i seen some where they had the wssm brass for under a buck.

This rifle is built ona Browning A-Bolt II. The donor rifle was chambered in .223 WSSM and was bought new, unfired.
It is a handy little thing. The barrel is pretty short at only 19" long.
I'm thinking longer bullets might be the cure. After all, none of the loads to date are compressed, so there should be some room for a bullet shank. We'll see....

 

[troy fairweather]

This rifle is built ona Browning A-Bolt II. The donor rifle was chambered in .223 WSSM and was bought new, unfired.
It is a handy little thing. The barrel is pretty short at only 19" long.
I'm thinking longer bullets might be the cure. After all, none of the loads to date are compressed, so there should be some room for a bullet shank. We'll see....

there is a gun shop by me he has had a browning 233 wssm on the shelf for over 4 years new with the box and about 100 rounds. i my walk in one day with some money and see what he needs to sell it for. he does ow me he had a ruger on the wall for 450. i looked at it saw it was a dog leg ruger varmint in 22-250 with a like new redfield on top. i told him the value of them and in 2 days he sold it for 1425. if i had the cash it would be in my case or 450 lol. where id u get your barrel from if i did one id get a mcgowen there under 300 short chambered. or a shaw if i get cheap.

 

[Poper]

My barrel On the Browning is a Shilen.
My 6.5-.300 WSM was a Montana Rifle Co.
Both are very good. I give the edge to Montana, tho. It seemed to clean up more quickly.

Be aware, according to the gunsmith that did the work on my A-Bolt II, the barrel swap was not easy. According to him, there was a thread locking compound used on the original and it has a very fine thread pitch. He said he had to clean and chase the threads in the receiver and that it was a real PITA. He asked me to NOT bring him another one!

 

[LoonWulf]

My barrel On the Browning is a Shilen.
My 6.5-.300 WSM was a Montana Rifle Co.
Both are very good. I give the edge to Montana, tho. It seemed to clean up more quickly.

Be aware, according to the gunsmith that did the work on my A-Bolt II, the barrel swap was not easy. According to him, there was a thread locking compound used on the original and it has a very fine thread pitch. He said he had to clean and chase the threads in the receiver and that it was a real PITA. He asked me to NOT bring him another one!

There are 2 thread types used on the browning Abolt2s. Mine had the courser threads, and no locking compound (2010 abolt), but it IS something to watch for. The stainless guns are also known to gal on installation and can be totally un-removeable.

There is a 6.5-wssm listed in quickloads, if you want to give me the bullets your using, and your COAL i can have it generate some data. While its not perfect ive found qloads to be decent at telling me if a combo im using is way out of range.

 

[LoonWulf]

Personally id probably try some 130-140s and the slower powders..rl-17, 19, and maybe superformance

 

[Poper]

There are 2 thread types used on the browning Abolt2s. Mine had the courser threads, and no locking compound (2010 abolt), but it IS something to watch for. The stainless guns are also known to gal on installation and can be totally un-removeable.

There is a 6.5-wssm listed in quickloads, if you want to give me the bullets your using, and your COAL i can have it generate some data. While its not perfect ive found qloads to be decent at telling me if a combo im using is way out of range.

Thank you very much for the offer! I just might take you up on it if my attempts with the 140 grain Sierra Game Kings doesn't pan out.

Interesting that you mention the SS situation. Though my receiver is CM, the Shilen barrel is SS. The gunsmith that did the work did say the next barrel swap could be it's last.... Oh, well, I doubt I will send enough lead out the end to wear it out. More likely I will get bored and try a new caliber. Maybe a 6.5 PPC....?

 

[Poper]

Next powder will be IMR4955.
Got two pounds just itching to push bullets out that tube!

 

[Poper]

UPDATE:...
Well, IMR4955 and 140 grain Sierras didn't work out. Excessive pressure signs were noted early in the load tests and at very moderate velocities.

Following LoonWulf's suggestion, I dug out the R17 and paired it with 120 Sierra SP and CCI-250 primers. Velocities were fairly good (2600-2800 fps) in the first loads. No signs of excessive pressure and one load showed some promise accuracy wise scoring in the 1.38" five-round group range. Further testing is on-going.

Looks like this little gun may have some potential after all...?
I hope!