colinbentley wrote:I am firing a Ruger 77 mark 2 using ADI powder AR 2209. According to reloading manuals loads for this should start at 37 grains but not to exceed 40 grains. I began at 37 and for a while stopped at 38 but recently had better groupings at 100 metres with 38.5, I am tempted to go to 39 grains but am a little concerned it is too close to the maximum. There are no visible danger signs at 38.5 (but I am no expert) Do the members consider it safe to go to 39 to see if that further improves accuracy ? Sorry forgot to mention the caliber is a 243 Winchester.
straightshooter wrote:colinbentley
It's not simply the powder weight that is important.
Go on the Hodgdon site and you will see a precise recipe which includes powder weight + projectile + COL and an indication of average chamber pressure for H4350=AR2209 in a 243.
Their recommended maximum should not be exceeded in any commercially made chamber.
As soon as you depart from their exact recipe, ie change bullet brand or COL or use in a match chamber, you in effect are on your own as far as safety is concerned due to the unpredictable effect the change may have on pressure.
It's not that the rifle will instantly blow up or that you might have to hammer the bolt open. What will happen with the repeated use of mild overloads is insidiously gradual and can range from short case life to locking lug set back.
Loads somewhat below published maximum won't have any of those problems and the difference in performance in the field will be imperceptible.
If you are inexperienced it is far wiser to use data that was developed under laboratory conditions by experienced technicians rather than follow the advice of anonymous internet commentators whose advice, often, isn't worth the paper it's written on.
Gwion wrote:The problem with saying 'watch for pressure signs' is that not everyone knows what to look for and as such could be skating on thin ice, slowly damaging their firearm or risking catastrophic failure. Accurate loads can be found I. The low-mid powder range with attention to details.
colinbentley wrote:I thought that powder grains were my problem so went to 39 grains only to discover that it made no difference to 38.5 grains. In fact I was most disappointed so thought to look elsewhere for my sloppy accuracy. I went back to square one and remeasured my bullet seating depth. Then set the bullet only 20 thou off the lands. problem overcome. Now shooting MOA , granted only 100 metres but I feel very proud to have overcome the problem. It's taken months to get there.I had made a miscalculation in the bullet seating depth. Dopey me.
sungazer wrote:A general note about reloading is that often the more powder in the loads the bigger the groups get at 100 however at longer distances they groupings may be smaller. this is due to the overall velocity of the round and when or if it transcends supersonic. (not always just related to supersonic/subsonic). The amount of powder the case consumes is a big factor as well as soon as the powder is compressed this can throw things right off. So try to find a powder that fills the case.
PS Dont forget that COL is for that bullet only. I have gone through all the bullets I have and worked out what the COL is. Most I cant put in the magazine so have to resort to single shot loading if i want that precision. The hunter bullets get made to the max of the magazine.
sungazer wrote:A general note about reloading is that often the more powder in the loads the bigger the groups get at 100 however at longer distances they groupings may be smaller. this is due to the overall velocity of the round and when or if it transcends supersonic. (not always just related to supersonic/subsonic). The amount of powder the case consumes is a big factor as well as soon as the powder is compressed this can throw things right off. So try to find a powder that fills the case.
PS Dont forget that COL is for that bullet only. I have gone through all the bullets I have and worked out what the COL is. Most I cant put in the magazine so have to resort to single shot loading if i want that precision. The hunter bullets get made to the max of the magazine.
sungazer wrote:A general note about reloading is that often the more powder in the loads the bigger the groups get at 100 however at longer distances they groupings may be smaller. this is due to the overall velocity of the round and when or if it transcends supersonic. (not always just related to supersonic/subsonic). The amount of powder the case consumes is a big factor as well as soon as the powder is compressed this can throw things right off. So try to find a powder that fills the case.
PS Dont forget that COL is for that bullet only. I have gone through all the bullets I have and worked out what the COL is. Most I cant put in the magazine so have to resort to single shot loading if i want that precision. The hunter bullets get made to the max of the magazine.
Gwion wrote:There are generally a few "accuracy nodes" for any given rifle and, in my view, the best way to find them is through comprehensive load development, not randomly jacking up charge weight. Best accuracy comes with consistent velocity, not necessarily higher velocity. Sometimes a long range hunter will sacrifice the most accurate node for one at a higher velocity for more lee-way when ranging a target but when you are talking about target shooting out further, it is a very consistent load and detailed D.O.P.E that gives the best results.
colinbentley wrote:God, you've lost me. Silly old bugger that I am thought it was just a case of put a bullet in the gun and squeeze the trigger. Taken me 12 years to understand headspace !Now you've totally confused me.
Gwion wrote:What you are referring to is the accuracy node. This is a balance of harmonics and consistent velocity. There is no way a load that does not have consistent velocity will provide a good water line elevation out @500yd and further.
You are looking for the area where charge weight has little effect on velocity while providing consistent harmonics.
http://precisionrifleblog.com/2012/07/1 ... r-testing/
Gwion wrote:The problem with saying 'watch for pressure signs' is that not everyone knows what to look for and as such could be skating on thin ice, slowly damaging their firearm or risking catastrophic failure. Accurate loads can be found I. The low-mid powder range with attention to details.
bigfellascott wrote:Gwion wrote:The problem with saying 'watch for pressure signs' is that not everyone knows what to look for and as such could be skating on thin ice, slowly damaging their firearm or risking catastrophic failure. Accurate loads can be found I. The low-mid powder range with attention to details.
They shouldn't be reloading if they don't know the basics hey. Any half decent reloading manual will show you what to look for in regards to pressure signs and how to reload safely, if they haven't got one of those I guess they will get what they get in the way of results good or bad.
And the other thing you will notice about different reloading manuals and information re loads and max/min is they all vary with the same powder so best thing one can do is reload with a view to keeping an eye out for diff pressure signs that will be the best indicator if one is getting into dangerous territory for their particular firearm or not.
Gwion wrote:bigfellascott wrote:Gwion wrote:The problem with saying 'watch for pressure signs' is that not everyone knows what to look for and as such could be skating on thin ice, slowly damaging their firearm or risking catastrophic failure. Accurate loads can be found I. The low-mid powder range with attention to details.
They shouldn't be reloading if they don't know the basics hey. Any half decent reloading manual will show you what to look for in regards to pressure signs and how to reload safely, if they haven't got one of those I guess they will get what they get in the way of results good or bad.
And the other thing you will notice about different reloading manuals and information re loads and max/min is they all vary with the same powder so best thing one can do is reload with a view to keeping an eye out for diff pressure signs that will be the best indicator if one is getting into dangerous territory for their particular firearm or not.
Yeah. Only thing with just reading a manual is that they are not all written in a way that makes sense to everyone. I had to read 3 and spend a good 6 months rehashing and pushing up the top end of powder loads before i started getting an idea exactly what pressure signs were. I'd like to see a manual with a full chapter devoted to pressure and detailed pictorials of what these different "signs" look like. I tried to start a thread on it to get some more experienced examples with pics and what not but it kind'a fell on its head.
A classic example is that most manuals refer to flattened or cratered primers but a lot of people claim that cratered primers are not a good indication. It's pretty obvious when your primer is well flattened, though. Just wonder how many people jump into reloading and never even look at the cases but just the groups!??!