7mm WSM: just checking...

[tikkathreebarrels]

Guys I've been measuring Cartridge Overall lengths for my recently acquired Howa 1500 7mm WSM. The seller, dropmdead, had advised me that the maximum length of round which fits into the magazine is significantly shorter than rounds seated for the lands.

Anyway, with supplies of 140gn Gameking Spitzers, 140gn Nosler Ballistic Tips, 162gn AMax and 175gn Matchkings and Stoney Point OAL Guage I've been measuring seating depth with each round to touching lands and also using a Sinclair Hex Style Bullet Comparator.

The SAAMI spec for 7mm WSM has an overall length of 2.860"

Each of the above bullets creates the following COL with in brackets the measured length to the point at which the bullet touches the lands:

140gn Gameking Spitzers: 2.971" at which length the bullet does not seat by 1 whole calibre (2.288")

140gn Nosler Ballistic Tips: 3.114" (2.441")

162gn AMax: 3.153" (2.405")

175gn Matchkings: 3.132" (2.425")


Initial thoughts are these:

1. My habit for the past 20 years has been to measure chambering to Max COL and then work back by 10thou. This has been a good starting point and I don't know of a reason why this wouldn't be an equally good starting point in this calibre.

2. I'm not worried by rounds being too long to fit the magazine: I can manage with single feed.

3. This rifle is going to do some duty as a deer rifle and some duty as an informal plinker and having a similar BC, weight and length of bullet for both roles will keep it simple. (I've tried using AMax on beasts and won't do it again. Okay they create a blood trail but I'd rather see more ballistic shock.)

4. I'm going shopping for a different bullet for deer duty, longer and heavier than 140 gn

Those of you using 7mm WSM: what bullets have you settled to using please?

Do you load to 10thou off the lands or some other distance?

 

[jcampbellsmith]

Have you had a read of http://www.ballisticstudies.com/Knowledgebase/7mm+Winchester+Short+Magnum.html or Nathan's latest book? Both might give you some pointers on what to do next?

Regards

JCS

 

[tikkathreebarrels]

Have you had a read of http://www.ballisticstudies.com/Knowledgebase/7mm+Winchester+Short+Magnum.html or Nathan's latest book? Both might give you some pointers on what to do next?

Regards

JCS

No I hadn't. (I had googled 7mm WSM but not found this) But I will now, thank you.

 

[see it shoot it]

Ive used a 7mm wsm for 10 years now and Iam on my 2nd barrel,just load to mag length with what ever bullet you choose.as to bullets use a non plastic tiped ones as they can be over long which will lead to far too much bullet in the case,I found Nosler Partion to be very good or Barns TSX,go for 150gr they will do everything you need
forget the lands as a factory rifle will be chambered to use every weight of bullet so you will have a long throat,seat to mag length and play with the powder also I found match primers better than magnum.
if using Winchester brass a light neck turn just to even the neck thickness out works wonders

 

[tikkathreebarrels]

Ive used a 7mm wsm for 10 years now and Iam on my 2nd barrel,

Ah, real life experience - just what I was hoping for. Thank you.

just load to mag length with what ever bullet you choose.as to bullets use a non plastic tiped ones as they can be over long which will lead to far too much bullet in the case,I found Nosler Partion to be very good or Barns TSX,go for 150gr they will do everything you need

Can I ask please, have you adopted this approach following experimentation or was this good advice which you've followed for ten years?

I can see how 150s will be a good compromise on mag length and how 175s will just have too much in the case if they're seated to suit magazine length rather than to get close to lands.

forget the lands as a factory rifle will be chambered to use every weight of bullet so you will have a long throat,seat to mag length and play with the powder also I found match primers better than magnum.

Really? So you're not troubled by a great distance for the bullet to jump to the lands? This has had no effect on load consistency and accuracy? You can see that I'm still working to overcome engrained instincts.

if using Winchester brass a light neck turn just to even the neck thickness out works wonders

Yes I'm currently on Winchester brass so I'm reaching for my Sinclair catalogue now!

 

[see it shoot it]

Ah, real life experience - just what I was hoping for. Thank you.



Can I ask please, have you adopted this approach following experimentation or was this good advice which you've followed for ten years?

I can see how 150s will be a good compromise on mag length and how 175s will just have too much in the case if they're seated to suit magazine length rather than to get close to lands.




Really? So you're not troubled by a great distance for the bullet to jump to the lands? This has had no effect on load consistency and accuracy? You can see that I'm still working to overcome engrained instincts.




Yes I'm currently on Winchester brass so I'm reaching for my Sinclair catalogue now!

yes real life experience and not shop counter hear say
I have tried all manner of seating depths and mag length works,at the end of the day its a hunting rifle so a quick second shot maybe needed so don't single feed.
buy a K&M tool there better reloading solutions stock them,well worth having as the brass becomes so much more consistent

 

[finnbear270]

Initially, stick with standard Large rifle primers, Magnum primers gave some inconsistent chrono readings in my rifle.

 

[Brithunter]

Really? So you're not troubled by a great distance for the bullet to jump to the lands? This has had no effect on load consistency and accuracy? You can see that I'm still working to overcome engrained instincts.

Whilst I don't have a WSM this comment just jumped out at me.

IMHO the "need" to be close to the lands in pure bunkum. In fact in my rifles I found quite the opposite. The time it really came home was back in 2003 when preparing for a trip to the US with my BSA CF2 in 7x57. I was using Hornady 139 grain Spire Points and needed to load up some more for the trip only to find none available. They had Hornady 139's but Hornady made three different 139's in 7mm at least back then.

So I picked up a couple of boxes of the 139BTSP to go and work up a comparable load as I already had some of the Flat pOint and whilst they shot small groups would not feed from one side the the BSA's magazine. The tip catching the edge of the chamber and jamming..

Trying the BTSP and it being the same weight I chose to try the same powder charge as the Spire Points and at the time believing the hype seated them close to the lands. Grouping was terrible. So the seating depth was played with a bit with no improvement and panic began to set in as time was running short and the BSA was the only rifle on my Temp Form 6.

Every possibly moment was spent at the range trying. Powder charge was played with as was eating depth to no avail. Then I made the decision to start from basics and forget all the BR hype. So I seated the bullet to it's cannelure over the powder charge that was good with the spire point and the group size shrank. We were now at least in acceptable hunting use size with the group being just over 1 1/2" at 100 yards.

So I played with the eating depth and this resulted in the bullet seated with the cannelure being about 0.040" (1mm) out of the case mouth and was producing groups of around 3/4" for Five shots. Once the tip was over I began to think more on this seating depth and it started to become clear than not only did this rifle prefer quite a jump to the leade but most of my rifles did.

Several were using bullets that it was simply impossible to have the bullet need the leade and it remain in the case mouth. Like the 6.5x55 with the 100 Grn Nosler Ballistic Tip of the Norma 77 grain bullet. The Rem PSP 100 grain bullet in the 270 Win of the Hornady 130 grn Spire Point in the 30-30 yet all short well.

If you read through other posts here at TSD you will notice others have found the same and bullet jumps of 1/6" or more is not uncommon especially with lighter bullets for the calibre (LFC + Light For Calibre) as often used in vermin control.

I now start with the bullets base seated to the neck shoulder juncture and work from there. Some bullets especially boat tails might have to go deeper but as i try to use flat based bullets where I can it often the case of working out from that starting point by 0.010" at a time.

Let me also say that I am no BR shooter just like I am no F1 driver and just like a F1 car would be useless on our roads a lot of BR techniques can stay at the bench as far as I am concerned.

 

[Muir]

Whilst I don't have a WSM this comment just jumped out at me.

IMHO the "need" to be close to the lands in pure bunkum. In fact in my rifles I found quite the opposite. The time it really came home was back in 2003 when preparing for a trip to the US with my BSA CF2 in 7x57. I was using Hornady 139 grain Spire Points and needed to load up some more for the trip only to find none available. They had Hornady 139's but Hornady made three different 139's in 7mm at least back then.

So I picked up a couple of boxes of the 139BTSP to go and work up a comparable load as I already had some of the Flat pOint and whilst they shot small groups would not feed from one side the the BSA's magazine. The tip catching the edge of the chamber and jamming..

Trying the BTSP and it being the same weight I chose to try the same powder charge as the Spire Points and at the time believing the hype seated them close to the lands. Grouping was terrible. So the seating depth was played with a bit with no improvement and panic began to set in as time was running short and the BSA was the only rifle on my Temp Form 6.

Every possibly moment was spent at the range trying. Powder charge was played with as was eating depth to no avail. Then I made the decision to start from basics and forget all the BR hype. So I seated the bullet to it's cannelure over the powder charge that was good with the spire point and the group size shrank. We were now at least in acceptable hunting use size with the group being just over 1 1/2" at 100 yards.

So I played with the eating depth and this resulted in the bullet seated with the cannelure being about 0.040" (1mm) out of the case mouth and was producing groups of around 3/4" for Five shots. Once the tip was over I began to think more on this seating depth and it started to become clear than not only did this rifle prefer quite a jump to the leade but most of my rifles did.

Several were using bullets that it was simply impossible to have the bullet need the leade and it remain in the case mouth. Like the 6.5x55 with the 100 Grn Nosler Ballistic Tip of the Norma 77 grain bullet. The Rem PSP 100 grain bullet in the 270 Win of the Hornady 130 grn Spire Point in the 30-30 yet all short well.

If you read through other posts here at TSD you will notice others have found the same and bullet jumps of 1/6" or more is not uncommon especially with lighter bullets for the calibre (LFC + Light For Calibre) as often used in vermin control.

I now start with the bullets base seated to the neck shoulder juncture and work from there. Some bullets especially boat tails might have to go deeper but as i try to use flat based bullets where I can it often the case of working out from that starting point by 0.010" at a time.

Let me also say that I am no BR shooter just like I am no F1 driver and just like a F1 car would be useless on our roads a lot of BR techniques can stay at the bench as far as I am concerned.

True that. It won't hurt, but there isn't much need; especially for hunting loads. The best factory match ammo produced is not loaded with any particular distance to the lands in mind. I made up some generic 30-06 this past week for my daughter: Small base FL resized and loaded to SAMMI dimensional specs. Shot 3/4" from her rifle from a loose rest. The same configuration of ammo from a different rifle, shot by someone who is not a very practiced markaman, gave 3/4 to 1MOA. In both cases never measured the distances to the lands and in one instance, never even handled the weapon before loading the ammunition. A month ago I did the same for some 308. The shooter -who is getting reloading lessons from me- said that ammo was the most accurate he'd ever used yet we never had the rifle in hand during the process. All just carefully made to SAAMI spec.~Muir

 

[see it shoot it]

True that. It won't hurt, but there isn't much need; especially for hunting loads. The best factory match ammo produced is not loaded with any particular distance to the lands in mind. I made up some generic 30-06 this past week for my daughter: Small base FL resized and loaded to SAMMI dimensional specs. Shot 3/4" from her rifle from a loose rest. The same configuration of ammo from a different rifle, shot by someone who is not a very practiced markaman, gave 3/4 to 1MOA. In both cases never measured the distances to the lands and in one instance, never even handled the weapon before loading the ammunition. A month ago I did the same for some 308. The shooter -who is getting reloading lessons from me- said that ammo was the most accurate he'd ever used yet we never had the rifle in hand during the process. All just carefully made to SAAMI spec.~Muir

Muir
as you know factory rifles will all have a long throat so they can use different weight bullets,so loading to the lands with the lighter bullet can cause problems IE not enough bullet in the case.
I always like to find out the OAL with the bullet Iam loading even if Iam not shooting off the lands.
if people are happy with 1 MOA accuracy ay 100 yards that's fine but what happens at further distance ???

 

[Brithunter]

if people are happy with 1 MOA accuracy ay 100 yards that's fine but what happens at further distance ???

You know what groups sizes normally get larger with distance. It's funny how that happens but it does.

Another funny thing is that I would hazard a guess than most people don't shoot their deer at any more than 200 yards and most a heck of lot closer.

I have just recalled my first stalking outing with Tony down in Sussex near Horsham. As it was my first outing with him he wanted me to shoot a target so he would know if I could hit it or not. Target shot with no dramas and off we went stalking. Later during the outing we cam to a junction of rides and he told me of a chap who had all the gear and often boasted of the tiny groups his expensive custom set up produced. yet he missed Roe Buck clean using sticks as a rest at 30 yards .

I have to thank you as I had not thought of Tony for a while and seeing your post brought this back plus a flood of other good memories of time spent with him .

 

[see it shoot it]

You know what groups sizes normally get larger with distance. It's funny how that happens but it does.

Another funny thing is that I would hazard a guess than most people don't shoot their deer at any more than 200 yards and most a heck of lot closer.

I have just recalled my first stalking outing with Tony down in Sussex near Horsham. As it was my first outing with him he wanted me to shoot a target so he would know if I could hit it or not. Target shot with no dramas and off we went stalking. Later during the outing we cam to a junction of rides and he told me of a chap who had all the gear and often boasted of the tiny groups his expensive custom set up produced. yet he missed Roe Buck clean using sticks as a rest at 30 yards .

I have to thank you as I had not thought of Tony for a while and seeing your post brought this back plus a flood of other good memories of time spent with him .

we can all miss mate,it usually the shots you think are easy probably like the one you mentioned,you cant take anything for granted.
as to group sizes getting larger at distance,thats why its best to get a nice small one at 100 yards as deer don't always stand at 100 yards or less

 

[tikkathreebarrels]

Well chaps, you're having a good crack at this aren't you? Please feel free to carry on. I'm obliged for all the opinions expressed to this point and will bear them in mind.

Experience has taught me that accuracy can have an effect on confidence and because I don't always wait for my deer to turn flank on and then shoot it "somewhere in the chest because that's good enough" I find that knowing that I have a tight group at 100 yards gives me confidence to know what's going to happen at 150, 200 and 250.

You know what? I'll work some up in the normal way then I'll load some with no reference to the lands and we'll see. I'm not saying you're wrong, not for one minute.

Primers, by the way, Federal Large Rifle Match.

 

[see it shoot it]

Well chaps, you're having a good crack at this aren't you? Please feel free to carry on. I'm obliged for all the opinions expressed to this point and will bear them in mind.

Experience has taught me that accuracy can have an effect on confidence and because I don't always wait for my deer to turn flank on and then shoot it "somewhere in the chest because that's good enough" I find that knowing that I have a tight group at 100 yards gives me confidence to know what's going to happen at 150, 200 and 250.

You know what? I'll work some up in the normal way then I'll load some with no reference to the lands and we'll see. I'm not saying you're wrong, not for one minute.

Primers, by the way, Federal Large Rifle Match.

Hi mate
you do the job which ever way your feel is best,I would be interested in your results,your right though on the confidence thing,an accurate rifle means confident shot placement,I darnt say what distances Iam happy to go out to I would be burned at the stake
federal 210 match is what I use,I found the magnum primers causes fliers

 

[Brithunter]

Unlike some I have no problems with those who can and do shoot at longer distances. We are not talking about the youtube vids now.

What I do maybe different to them but that's just me. One American friend feels it's unsporting to shoot deer at under 300 yards. Oh he will do so, when I was with him he took his buck at 65 yards, the year before it was at 325 paces, undoubtedly he is a better shot than I. Another American friend also shoots his deer at longer distances than I would normally do but again where he lives it's very flat with little to no cover so getting up close is very difficult. How can one say it's unethical when their results speak for them selves.

Which reminds me I must check how Dan is fairing as he is having to use a lighter calibre and rifle this year due to a rather nasty incident whilst rounding up the cattle earlier in the year. He came a cropper off the ATV and fractured his neck.

 

[Muir]

Muir
as you know factory rifles will all have a long throat so they can use different weight bullets,so loading to the lands with the lighter bullet can cause problems IE not enough bullet in the case.
I always like to find out the OAL with the bullet Iam loading even if Iam not shooting off the lands.
if people are happy with 1 MOA accuracy ay 100 yards that's fine but what happens at further distance ???

I think you will agree that at long distance, say, over 200M, the wind and shooter's ability play more hell with accuracy than whether it's a half MOA load or a full MOA load. A half minute load becomes less impressive in a 15mph cross wind at 300 yards when shooting across varying terrain and in fact may be for practical purposes, no more accurate than the 1 MOA load once the up drafts and down drafts and cross drifts get done with it. I think insisting that a hunting cartridge shoot 1/2 MOA because it will be used at long range is to assume you are shooting in a vacuum.

But don't get me wrong. I like half MOA hunting rifles and take pride in loading for several of them. Loading out to any specific distance to the lands, however, has not been the reason they shoot half-MOA. I also will measure the bullet to the throat for max OAL and see how it will compare to the magazine but I never base my starting OAL by that measurement because it is no guarantee of accuracy. I have often voiced my hillbilly method for determining my initial OAL so I won't repeat it here. Suffice to say that I have never attributed the accuracy of a load to a specific distance from the lands, nor have I targeted a specific distance from the lands to achieve accuracy.

My examples of the loads I made in 30-06 and 308 should be taken into the proper context. These were not tweaked or worked up. These were made without regard to the specific rifle they were to be fired in. One powder charge used in each caliber with no further adjustment or tuning to bring them to a MOA or sub MOA level. In two of the cases (the 308 and one of the 30-06's) I never even laid eyes on the rifles, let alone measured the distances to the lands. Yet the ammunition gave what I think are respectable results and in the end, killed mule deer between 150 and 250 yards with no difficulties.

If I may say so, these loads were very fine handloads. All the same LOT brass. All trimmed to the same length after Small Base Full Length resizing to assure interchangeability, primer pockets uniformed, necks flared to aid in straight bullet seating. The powder was chosen for it's appropriateness for the bullet weight and case capacity and the charges dropped with a super accurate measure. The bullets were seated with care to SAAMI spec (or close to it) and finally, crimped into place with the Lee FCD for uniformity of pull weight. In essence, they were equal or better than the best factory ammunition in care of construction. While they were not tailor made to a particular rifle and perhaps weren't what will prove to be top notch performers in any of them, they were very uniform and gave good results because of it.

I will admit that adjusting the seating depth a bit in or out to suit a particular rifle might give better accuracy but it was obviously not the place I began load development from. Instead it was the last place I went.~Muir

 

[Brithunter]

But Muir that's just plain wrong .................................. all the experts seat so many thou off the leade so it MUST be wrong .

 

[see it shoot it]

But Muir that's just plain wrong .................................. all the experts seat so many thou off the leade so it MUST be wrong .

no one said it wrong,or I have missed something,Muir clealy states adjusting your seating depth can improve accuracy,its all down the the individuals requirements and accepted accuracy
also on the other side of the coin what Muir is doing maybe see as wrong to others.

 

[Muir]

no one said it wrong,or I have missed something,Muir clealy states adjusting your seating depth can improve accuracy,its all down the the individuals requirements and accepted accuracy
also on the other side of the coin what Muir is doing maybe see as wrong to others.

I think Kevin was just toying with us.

Thanks. I do believe that adjusting depth can effect accuracy. I just don't believe that seating out to the lands is always the way to go and smirk when people say definitively that X-thou gives best accuracy. That's nonsense. There are so many other things a person can attend to before fretting about seating depth.~Muir

 

[see it shoot it]

I think Kevin was just toying with us.

Thanks. I do believe that adjusting depth can effect accuracy. I just don't believe that seating out to the lands is always the way to go and smirk when people say definitively that X-thou gives best accuracy. That's nonsense. There are so many other things a person can attend to before fretting about seating depth.~Muir

I have a rifle that shoots kissing the lands,but to be fair that's how I had it chambered with zero free bore,Ive never come across another rifle in the same calibre that shoots like it