Hi, I just started reloading a few months aga and have a beginners question. I have a RPR 6.5 creedmore that is incredibly accurate. I actually get disappointed when I shoot cloverleafs because I get raged 4 shot holes quite often. Last time I went out I got disappointed and went home after around 20 shots. I could barely get under 1 moa, it was like I was shooting a different riffle. One of the guys at the range told me that it was because of the temperature difference. Earlier in the year the days were 70°F or higher and that day was around 50°F instead . My usual load is Hornady eld-m 140gr. with 40gr. of h4350. Could someone please enlighten me on how this load could be changed to make up for colder days or direct me to a page where I can learn about this. thanks for any help in advance.
reloading for different temperatures
- Thread starter Al A
- Start date
For colder days you can add more powder to make up the missing energy.
To actually test it put the test rounds in a cooler and keep them cold until right when you shoot them.
Here the results of when I tested my 6xc with H4350 and RL16 with ammo temps of 35, 85 and 120 degrees.
To actually test it put the test rounds in a cooler and keep them cold until right when you shoot them.
Here the results of when I tested my 6xc with H4350 and RL16 with ammo temps of 35, 85 and 120 degrees.
I chrono'd several times at different temps, especially low temps since it's mostly hot hear in Texas. My results were high consist with H4350 on an RCBS and Prometheus.
What powder scale are you using? Are you seating depths consistent?
What powder scale are you using? Are you seating depths consistent?
Thanks for your replies, I have a lyman accu 2000 so my loads are pretty consistent give or take a 10th of a gr. The bullets are seated as recommended on the hodgdon data site. I also full size the brass and keep it at recommended length . I live in Canada and will not probably go out often untill spring gets here but next time the temp goes up to around 50°F I will have a few different loads ready increased at .3 grains increments to try out. thanks again I appreciate the help.
Somehow I managed to miss this post yesterday and managed to post almost the same exact question. I am having exactly the same problem you are having and wondered how everyone was dealing with it. I live in Maryland so we have some pretty big temperature swings. High 90’s in the summer and close to 5-10 degrees in the winter. I think the cooler may Ben the answer for me. I use a RCBS charge master to weigh my powder and I have a Hornady Match die set with the changeable bushing. My SD is consistanly under 10 in the summer so I think my loads are consistent enough considering I’m fairly new at this. I’m defiantly seeing a much bigger velocity swing than Spife is seeing. My difference is closer to 100 FPS which is just enough apparently to really mess up the loads accuracy. My powder is all the same lot and the only thing that has changes is the temperature so that is the only thing I can figure is making the difference.
Hi Eoddave27, nice to hear from you. I don't even have a Chronograph yet but can see that it should be my next purchase. I'm finding this sport complex and supper challenging. Just the thing for me now that I am retired and have a ton of time on my hands. Wish I had a ton of money on my hands too lol. I'm thinking of getting the magnetospeed sporter but need to do some research on how well it performs first. Thanks for your reply .
I did a test by placing some ammo that I loaded up in ice, and hot water before I left on the 2 hour drive to the range.
AA2520 and RL26 shot at 15*, 59* 70* and 115*. The AA2520 5 shot average for each temp was a whopping 24 FPS, SD and ES stayed consistent.
RL26 was under 10* from 15* to 115*. The most it did was skew my SD from 4.9 to 13.3
I got more velocity drop by seating .008 deeper (50 FPS) for a shorter mag.
AA2520 and RL26 shot at 15*, 59* 70* and 115*. The AA2520 5 shot average for each temp was a whopping 24 FPS, SD and ES stayed consistent.
RL26 was under 10* from 15* to 115*. The most it did was skew my SD from 4.9 to 13.3
I got more velocity drop by seating .008 deeper (50 FPS) for a shorter mag.
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Ive never noticed any accuracy differences shoot at 50 degrees or 80 degrees. The biggest factors for me, as with anybody else, is wind. Ive also noticed that humidty can effect velocity/accuracy. As well as shooting at noon or late evening.
Its mostly just POI shifts of 1/2 MOA or so.
Its mostly just POI shifts of 1/2 MOA or so.
You may also be on the high side of your accuracy node if you developed it in cooler temps, once the temp warmed up it bumped you just outside or over that node.
That's just a possibility but doubtful since you are only talking about a 20° difference and are using one of the most temp stable powders but one thing to check.
I prefer to do load development in 90+ degree weather so I have my theoretical max and have fewer surprises, mainly over pressure loads.
I would go back over everything on the rifle and verify nothing has come loose.
One other data point I didn't see listed is round count on the barrel, if the barrel was shooting as you state when new and now it is broken in that velocity change could also be having an effect on your group sizes and charge weights. I would go back over you chrono data and review your starting velocities and compare to current.
That's just a possibility but doubtful since you are only talking about a 20° difference and are using one of the most temp stable powders but one thing to check.
I prefer to do load development in 90+ degree weather so I have my theoretical max and have fewer surprises, mainly over pressure loads.
I would go back over everything on the rifle and verify nothing has come loose.
One other data point I didn't see listed is round count on the barrel, if the barrel was shooting as you state when new and now it is broken in that velocity change could also be having an effect on your group sizes and charge weights. I would go back over you chrono data and review your starting velocities and compare to current.
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