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25 wssm Coyote

By ADMIN · Aug 28, 2016 ·
Rating:
5/5,
  1. ADMIN
    25 wssm Coyote

    By Robert Coles

    The series of Winchester super short magnum cartridges never really started any fires with the interest of shooters. You can read many threads of why these (223wssm, 243wssm, 25wssm) rounds are undesirable, along with reloading issues and touchy pressure spikes.

    [​IMG]



    I found a very lightly used Winchester model 70 Coyote, chambered in 25wssm. These rifles have a nice look with the laminated stock, matte finished receiver and stainless barrel. This one saw very little use with approximately 80 rounds down the bore. The previous owner claimed ¾” groups with handloads using 100 grain bullets at 100 yards are the best this rifle will print, and doubted tighter groups could be produced.

    The price was right and the rifle looked good, so off to the bench for a really good barrel cleaning was first up on the list. Those were some deep blue colored patches that kept getting pushed out of that 24” varmint taper barrel ( I’ll cover some bore cleaning methods in a later writing ). Disassembly revealed good stock bedding, free floated barrel and solid scope mounts with Burris rings.

    The factory twist barrel was 1-10, allowing a good selection of bullets, so I picked the 120 grain Winchester “pep” ammo at 3000 fps to check for accuracy. This would be a very good choice for those Michigan deer this fall. I did one small adjustment to the factory trigger after installing a lighter weight sear spring and was able to tune a nice clean breaking 1.5LB trigger pull.

    The morning was a mild spring day and I settled the 25wssm in the sand bags, then adjusting a Weaver Grand slam 6-20×40 scope on the 100 yard target, I fired the first three rounds to produce an unimpressive +1” group, which should tighten up once this very clean bore fouls a bit. Taking time between shots with a larger bore diameter helps evaluate groups better while controlling barrel overheating. The next three rounds printed a very nice ½” group that will work well for larger game, and already this average shooting rifle was showing some accuracy potential!
     

    25 wssm Coyote

    With a proper barrel cleaning, trigger tuning and good shooting technique box stock (kinda) rifles can produce very good accuracy. Now we will go after some really fast velocity along with good accuracy for the varmint loads, these will be handloads directed at squeezing out the best performance using a 75grain Hornady A-max bullet that will be focused at reaching 3600fps.

    [​IMG]



    Stay tuned in for range results on the 75 grain varmint loads…I was surprised at the powder of choice I ended up with.

    Testing 75 grain varmint loads, a surprising powder came out the winner

    Varmint loads…velocity with a good bit of accuracy to boot! The target fps I wanted to have was 3600 along with tight accurate grouping. I had some varieties of powder on hand however I will admit while sitting on 8+ pounds of IMR4064 I was driven to make that powder work! Funny how things work out and I did learn some unique traits of this short fat powerhouse of a .257 caliber.

    *ALL LOADS REPRESENTED IN THIS ARTICLE ARE SAFE IN THIS RIFLE. DO NOT DUPLICATE ANY LOAD INFORMATION LISTED UNLESS YOU REDUCE THE CHARGE AND WORK UP SLOWLY. SOME OF THESE LOADS ARE NEAR MAXIMUM ACCORDING TO PRINTED RELOADING MANUALS*

    I start by prepping my fired cases with a shoulder bump die three thousands less than fire formed length, I used a Sinclair shoulder bump gauge and a caliper. CCI BR2 primers are used thru out all the load development (I have found them to be good performers in past cartridge/load work and they are my go to primers ). These wssm cases have the thickest necks you will find (.022”) on the average, I turned the necks to .014” thick and will talk more about that later……ughh. Hornady V-max was the bullet of choice at 75 grains and IMR4064, Varget and IMR4320 were the powders.

    Starting loads with what I thought was a great powder (since I had so much of it). A quick run thru Quick Load gave me starting charges along with safe estimated chamber pressures. A shoulder bump length of 1.218 measured with gauge and cartridge overall length (C.O.L.) ranging from 2.340” – 2.380”, 45.5 up to 46.3 grains of IMR4064 was sitting under a 75 grain v-max, ignited by a CCI BR2 primer.

    25 wssm Coyote

    Plenty of test loads and now some range time, I soon found out 4064 was not going to get along with this 25wssm no matter how bad I wanted it to, nothing grouped better that ¾” with erratic flyers, along with this struggling attempt I decided to turn the case necks to .014” and a C.O.L. of 2.360” was picked. With necks turned and 46 grains of IMR4064 loaded in groups were still terrible and now I was splitting necks on cases fired twice. Lesson learned. Don’t turn the wssm necks on a factory chambered rifle.

    [​IMG]



    Giving up on IMR4064 I moved to Varget and started with a C.O.L. of 2.360” and after various load charges I settled with 47 grains and a nice 3600 fps. Sounds good except the groups were all 1+” all over the paper! I remembered reading an article on the wssm cartridges, the author mentioned bumping the shoulders just a little more to eliminate what he called the wssm sticky bolt.

    A new shoulder bump length of 1.212” measured with a gauge, 47grains of Varget, then set a v-max down the neck and back to the range. The fraction extra shoulder bump was the trick to smooth extraction with the wssm case but groups still did not improve with the switch to Varget powder. Not getting groups better than 1” at 100 yards had me putting the Varget back on the shelf now on the IMR 4320.

    With a C.O.L. of 2.360, CCI BR2 primers, factory Winchester cases with unturned necks and 75 grain V-max’s I started yet another try at getting this rifle to cooperate. A clean bore and proper bench setup set the stage for these loads: IMR 4320 @ 46.5, 47, 48 grains as usual I started with the low charge looking for pressure signs while measuring group size. Three shot strings would be checked for down range results and slow fire timed shots will keep the barrel form heating up to quickly.

    The day wrapped up with these results: 46.5 grains @ 3565 fps, dirty case necks and 3/4″ groups. 47 grains @ 3601 resulted in clean necks, better groups but a nasty flyer opening the group to 1.1/4”. Finally 48 grains @ 3681 fps produced ½” groups, nice brass but still somewhat larger groups than I wanted. I prepped some brass and loaded a slightly lower charge @ 47.4 grains to try and sweeten up the load.

    Touching off rounds at the bench give their own type of satisfaction and this range day was no slouch! With three shots measuring a tiny ¼” and clocking in at 3625 fps, a nice accurate varmint load was found and boy was I happy. One tight group does not evaluate a load as “the one” so I loaded up twenty proof rounds with 47.4 grains of IMR 4320 for another days shooting.

    A nice cool 15 degree Michigan day with little to no wind had me kicking snow away from the 100 yard backstop. The pet load still produced tiny bug hole groups consistently so I went and shot a group with six rounds knowing my odds were good at opening up the group. I posted a picture of the group showing four of the rounds in a ¼” hole with two opening the group to ½”. I would never have thought IMR4320 would be such a good performer in this round and this brought me to remembering the wildcat 22-284 I build previously.

    Looking at ballistics between the two with one a .22 caliber and the other a .25 caliber, both shooting 75grain V-max’s at close to the same velocity. Bullet drop being very similar at extended ranges I highly doubt a crow would know the difference between the two cartridges as he turns to black dust. Case forming for the 22-284 is required while the 25wssm was a factory round, funny how close these two cartridges preform and it will be a tough choice which one will see more field use in the crow fields with me.

    25 wssm Coyote

    Plenty of test loads and now some range time, I soon found out 4064 was not going to get along with this 25wssm no matter how bad I wanted it to, nothing grouped better that ¾” with erratic flyers, along with this struggling attempt I decided to turn the case necks to .014” and a C.O.L. of 2.360” was picked. With necks turned and 46 grains of IMR4064 loaded in groups were still terrible and now I was splitting necks on cases fired twice. Lesson learned. Don’t turn the wssm necks on a factory chambered rifle.

    [​IMG]



    Giving up on IMR4064 I moved to Varget and started with a C.O.L. of 2.360” and after various load charges I settled with 47 grains and a nice 3600 fps. Sounds good except the groups were all 1+” all over the paper! I remembered reading an article on the wssm cartridges, the author mentioned bumping the shoulders just a little more to eliminate what he called the wssm sticky bolt.

    A new shoulder bump length of 1.212” measured with a gauge, 47grains of Varget, then set a v-max down the neck and back to the range. The fraction extra shoulder bump was the trick to smooth extraction with the wssm case but groups still did not improve with the switch to Varget powder. Not getting groups better than 1” at 100 yards had me putting the Varget back on the shelf now on the IMR 4320.

    With a C.O.L. of 2.360, CCI BR2 primers, factory Winchester cases with unturned necks and 75 grain V-max’s I started yet another try at getting this rifle to cooperate. A clean bore and proper bench setup set the stage for these loads: IMR 4320 @ 46.5, 47, 48 grains as usual I started with the low charge looking for pressure signs while measuring group size. Three shot strings would be checked for down range results and slow fire timed shots will keep the barrel form heating up to quickly.

    The day wrapped up with these results: 46.5 grains @ 3565 fps, dirty case necks and 3/4″ groups. 47 grains @ 3601 resulted in clean necks, better groups but a nasty flyer opening the group to 1.1/4”. Finally 48 grains @ 3681 fps produced ½” groups, nice brass but still somewhat larger groups than I wanted. I prepped some brass and loaded a slightly lower charge @ 47.4 grains to try and sweeten up the load.

    Touching off rounds at the bench give their own type of satisfaction and this range day was no slouch! With three shots measuring a tiny ¼” and clocking in at 3625 fps, a nice accurate varmint load was found and boy was I happy. One tight group does not evaluate a load as “the one” so I loaded up twenty proof rounds with 47.4 grains of IMR 4320 for another days shooting.

    A nice cool 15 degree Michigan day with little to no wind had me kicking snow away from the 100 yard backstop. The pet load still produced tiny bug hole groups consistently so I went and shot a group with six rounds knowing my odds were good at opening up the group. I posted a picture of the group showing four of the rounds in a ¼” hole with two opening the group to ½”. I would never have thought IMR4320 would be such a good performer in this round and this brought me to remembering the wildcat 22-284 I build previously.

    Looking at ballistics between the two with one a .22 caliber and the other a .25 caliber, both shooting 75grain V-max’s at close to the same velocity. Bullet drop being very similar at extended ranges I highly doubt a crow would know the difference between the two cartridges as he turns to black dust. Case forming for the 22-284 is required while the 25wssm was a factory round, funny how close these two cartridges preform and it will be a tough choice which one will see more field use in the crow fields with me.

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