.243 load development help please

[Ballie]

I had posted this in the reloading section but as I have had no replies I thought I would try here as well.

 

With the help of a friends reloading kit I am trying to develop a home load for my Tikka T3 .243. All the loads I made where with 40g of Varget and 70g noz-bt and shot from a 22†barrel.

 

The 1st load was with a over all bullet length of 2.701†with a average fps of 3149

 

The 2nd load was with a over all bullet length of 2.720†with a average fps of 3220

 

The 3rd load was with a over all bullet length of 2.740†with a average fps of 3265

 

As you can see the bullet is getting faster (with the same amount of powder) the further out of the case it is set! Why is this?

 

The other thing that I find very strange is that Hodgdon state that 38g of varget in a .243 produces 3433 fps with 40.5g producing 3574 fps. So why should my loads produce speeds 300 fps slower than this?

 

The only thing that I can think of is the pot of varget I have used is about 6 years old, could this make a difference?

 

What has really surprised me is that I tried a couple of factory loads (federal v-shok 70g noz-bt) and they came out at an average of 3405 fps!!! I would have thought that factory loads would not have been as fast as 40g varget!

 

Can any of you home loaders shed any light on this. BTW the 2nd group shoot best at .60 of an inch at 100 yards. But I would like a bit more FPS if possible.

[DaveK]

So in amongst all this technical stuff you're not saying how the loads are performing.

 

The important thing is to find a configuration that works for your rifle so a combination of load, bullet seating, primer, etc. Once you have the ideal load thats giving you consistent groups, then see how fast its going.

 

My rifle likes 44gn Viht N160 with a 75gn V-Max. No idea how fast its going but it groups like **** to a blanket at 100 yards woth foxes out to 200+ and that does it for me.

 

Dave

[Ballie]

Can any of you home loaders shed any light on this. BTW the 2nd group shoot best at .60 of an inch at 100 yards. But I would like a bit more FPS if possible.

 

DaveK, I have said the 2nd load shoot a .60 inch group at 100 yards.

[mry716]

I cannot tell you all the ‘whys and wherefores’ but hopefully give you a pointer or two for you to find out for yourself.

 

 

“ you can see the bullet is getting faster (with the same amount of powder) the further out of the case it is set! Why is this?â€

 

As you load your bullet closer to the rifling it has less time to break free from the case neck and build up speed to push into the rifling. This tends to increase pressures and therefore terminal velocity.

If you pushed your bullet into the lands and had a tight neck on your case you could in theory increase your pressures so much that you could damage the rifle. In fact I have actually seen a cracked action simply from that cause.

 

As an aside – one of the most important aspects of reloading and certainly one that is paramount for safety is case length. Always trim when the cases are verging on being max length and never omit to do so. A neck crimped into the bullet will increase pressures beyond belief. I also suggest you do not push your bullets closer than 20-25 thou off the rifling. Most rifles will show inconsistencies and you could have a mishap by pushing closer without being quite an advanced loader. Also it is only normal with special target bullets or specific cartridges such as the Weatherby calibers.

 

 

“The other thing that I find very strange is that Hodgdon state that 38g of Varget in a .243 produces 3433 fps with 40.5g producing 3574 fps. So why should my loads produce speeds 300 fps slower than this?â€

 

Because your rifle and the components used are not identical to the Hogdon setup you cannot expect identical performance. Hogdons test equipment will be as near perfect as money can buy in order to avoid any errors in their data. Even the size of your chamber can alter pressures by a noticeable amount and reduce velocity by up to 100-150 fps. The case will expand on initial firing of primer and the start of the burn before the bullet starts to leave the case. This reduces pressure which needs to build up again to push the bullet forward. The larger the gap around the case to the chamber wall the lower the pressure falls and the lower the resulting velocity. But NEVER exceed factory velocities of ammo shot in your rifle. Choosing a load that shows no signs of pressure and checking the velocity is the best and safest way to achieve good consistent and fast loads. If you see no pressure signs and have not reached the same velocity as factory (or within 100 - 200fps as a safety margin) you should be fine to carry on increasing your load.

 

These experiments become second nature with experience so if in any doubt as to your capability to judge the signs of pressure accurately at the moment do not do it.

 

“The only thing that I can think of is the pot of Varget I have used is about 6 years old, could this make a difference?â€

 

If powder is stale it will smell a little of ‘Pear Drops’. If it does take it outside and have a firework display but don’t use it in your ammo. It is most unlikely to be ‘off’ unless it has become damp. I have reloaded and fired ‘cordite’ made in 1914 and it was still ok.

 

 

“What has really surprised me is that I tried a couple of factory loads (federal v-shok 70g noz-bt) and they came out at an average of 3405 fps!!! I would have thought that factory loads would not have been as fast as 40g varget!â€

 

The factory loads often use powders that we as reloaders are not able to buy. The Vhitavouri N500 series gave the ammo makers a bonus over the N100 series which we were using until we also were able to purchase the N500 series. The same is presently true for the powder used in some of the WW 204 ammo and some of the Federal Light Magnum range of cartridges.

 

“Can any of you home loaders shed any light on this. BTW the 2nd group shoot best at .60 of an inch at 100 yards. But I would like a bit more FPS if possible.â€

 

I have loaded many 100s of 1000s of rounds over the years and have always found the best accuracy is below max velocity. In fact often 5% below max load, dependant on cartridge and powder. If you are getting good accuracy by all means try more powder but you may find you drop back again.

 

Consistent shots are far more important in the field than max velocity.

 

I could go on and on but hopefully the above will give you something top think about and ideas for more questions.

Regards,

M

[JRDS]

As far as I know alot of quoted velocity stats from Manufacturers of powder or factory ammo are from long barrels, in the instance of the 243 a 24 or 26 inch and a longer burn = more velocity.

 

Far more important than the odd 100 fps or more is the accuracy :unsure:

[Ballie]

Thank mry716/JRDS

 

I am going to try another 1/2 - 1 grain of powder just to see, the bullet is 40 thou from lands at present which shoots better than 20 thou from lands.

 

I will post back with some targets next week

[deadeye ive]

This is one area i can't offer any advice but maybe you could give me some .........It's about your chrono

What type is it ,how much and what is your opinion on it please . :unsure:

[Ballie]

Ive, it is not mine it is a friends but this is it http://www.midwayuk.com/apps/eproductpage....leItemID=306796 it seems very good but it wouldn't read my .17hmr at all!

 

Regards

[DaveK]

Can any of you home loaders shed any light on this. BTW the 2nd group shoot best at .60 of an inch at 100 yards. But I would like a bit more FPS if possible.

 

DaveK, I have said the 2nd load shoot a .60 inch group at 100 yards.

 

ooops, never noticed that bit :(

 

 

.6" at 100 yards is nothing to sniff at. You're talking thumbnail groups and you'll not get much better. If it's doing the job without why do you need the extra fps? If it's to hoik the bullet out to a good distance try zeroing at 150 or 200 yards rather than 100 with what you've got now.

 

Dave

[Ballie]

DaveK, I agree with what you say and I have in fact now zeroed 1" high at 100yds which shoots

 

1/2" low at 200 yds,

3" low at 250 yds

7" low at 300 yds.

 

But just for info I want to see what happens when I increase the load, which I will do 1/2 grain at a time. However I will not give up accuracy for more FPS, but if I can get more FPS with no loss of accuracy then job done!

[mry716]

Just had an idea.

 

Drop back a grain and try the next hotter primer instead of increasing the load.

What are you using presently?

[DaveK]

DaveK, I agree with what you say and I have in fact now zeroed 1" high at 100yds which shoots

 

1/2" low at 200 yds,

3" low at 250 yds

7" low at 300 yds.

 

But just for info I want to see what happens when I increase the load, which I will do 1/2 grain at a time. However I will not give up accuracy for more FPS, but if I can get more FPS with no loss of accuracy then job done!

 

 

Normally the zeroing you mention is exactly as I do it but what about spread as you go out further. 1" high at 100 yards may give .5 inch low at 200 but how much will the grouping expand? Can we expect as tight a group at 200 from a 100 yard zero?

 

Dave

[deadeye ive]

1/2" low at 200 yds,

3" low at 250 yds

7" low at 300 yds.

For a .243 70grn bullet with 40 grns of powder behind it that is some drop or am i missing something :( .....That trajectory is very similar to my .223 except I'm on the nail at 200 yds for being 1" high at 100 yds

 

Time to get the anorak out again .......have a play with this has it looks like you've got all the relevant data

http://www.eskimo.com/~jbm/ballistics/traj/traj.html

 

it's very accurate believe it or not ....good Luck

 

Can we expect as tight a group at 200 from a 100 yard zero?

 

Dave

My rifle is zero'd at 100 yds and I actually shoot better at 200 yds but that's down to me I feel and not the bullet ,.........probably down to the fact that the cross air is'nt dancing about as much .

[Ballie]

mry716, the primers I used are CCI bench rest, (I prefer federal, but couldn't get them) I did not know that a different primmer would make any difference, please can you tell me a bite more about this.

 

Ive, I do have some ballistic software and an anorak! the software I use is Barnes and Point blank but I must say the link you just gave me is very good indeed, in fact I think better!

 

However whatever software you use the drop of the .243 bullet is the same, try it on your pc, the ballistic coefficient of a 70g Noz-BT is 0.310, the FPS is 3200 at muzzle the height of sight above bore is 1.75". I think some people will be surprised that a 70g .243 round is not as flat shooting as some might think.

[mry716]

You should choose your primers as you do your powder, according to the burn rate?

 

Primers can be hot or cool or in between and alter your load very significantly. Try changing and you may be surprised just how much your load changes. Not only that you may be surprised how one primer that seemingly was not particularly satisfactory in one load becomes the 'bees knees' in another. DO NOT CHANGe PRIMERS WITHOUT REDuCING POWDER LOADS. You could easily have a mishap such is the significance of the differences in pressure levels one primer to another.

 

You really should try it !

 

The guide for the main primers below shows the 'Hottest' at the top and on each line shows the equivalent for large and small rifle down to 'Coolest' at the bottom

 

Fed 215 and Fed 205

 

WLRM and Rem 71/2

 

CCI250 and WSRM

 

Rem 91/2M and WSR

 

WLR and CCI BR4

 

Fed 210 and CCI400

 

CCI BR2 and Fed 200

 

(Sorry but the site doesn't allow tab spacing .

Intersperse other makes according to how you find them.)

 

The secret is to use the primer that gives the best consistent burn, round to round dependent on the powder and case used not necessarily the highest velocity.

 

The same style of powder in larger diameter cases (eg the WSM and WSSM style of case) generally burns better with a hotter primer. So whereas in the 308 I may use a standard CCI LR primer with N140 - In the 300WSM with the same 165grn bullet weight I would choose the CCI 250 or even the WLRM and N160. Powder grain size is approx the same so the density of the load is approximately equal but the hotter primer will give a more even and faster, better burn towards the sides and on to the top of the case in the 300WSM so ensuring a full consistent burn and proportionally slightly higher velocities. More importantly there is less chance of a partial or spaspodic burn so helping consistency round to round.

 

Another example. For those that shoot 243. If you use H4831 then use say Fed 210 as the starter, but if you choose H4831SC then go one or even two grades hotter to say WLR, Rem 91/2 or even CCI250 if you are filling the case.

 

If you use a ball powder it is always advisable to choose a decidedly hotter primer and generally a Magnum one. Winchester ball powder prefers the WLRM primer and accuracy often improves by choosing it over say the CCI or Rem magnum primer.

 

The same applies to compacted or compressed loads. Increase the heat of the primer by at least one point and I also usually try a magnum primer - often to the benefit of consistent velocities.