New guy reloading 260 Remington

Thanatos-Keres

Private
Minuteman
Oct 12, 2021
19
1
Chicago
Hello all!

Sorry for the long post but as a new guy here going down the rabbit hole of reloading. I am slowly getting things together to start reloading my ammo. I understand it's a pretty bad time to get into it e.g. supply issues. In the meantime as things come in the mail. Ide love some advice, tip/tricks about reloading this caliber, and answers to my questions as they come up.

To start, I went with 260 because after some research I found that since I wanted to get into reloading, compared to 6.5 creedmoor the 260 is not much different, reload friendly, shoots flatter than the 308 while being nicer to my shoulder, and creed just seemed a little too new for me.

As my first rifle and budget build, a Remington M700 PCR in 260 Remington. Topped off with a Vortex Diamondback Tactical FFP with a Precision Armament Hypertap MB. She's had about 200 factory rounds thru her and I'll be starting my load dev from the used brass.

Starting with the factory Hornady match ammo. She liked the 130gr ELD-M rounds as I kept 5 round groups under .75" @ 100yards with a usual flyer(Albeit my first time @100 yards I'm quite happy with the result.) 3 round groups were even tighter, and was satisfying.

Anyway, Thats where I'll be starting loads with the Hornady brass ive saved. Leading to my first few questions:

In regards to the bullet I use, am I safe to assume that most people used a 6.5mm creedmoor round in a 260 case due to the same bullet día.? I can't seem to find specific 260 bullets anywhere(I guess first problem with going 260 Rem?)

Next, does the longer 6.5 creed round compress loads by a lot? I know I can and will seat longer if I have to, as far as my mag will let me. But if I can use em I want to go with the Hornady 130gr ELD-M BT to start, with Hornady brass and eventually good primers and powder whenever that's back in stock. I will eventually try out different brass and bullets as time goes on, but this is my starting point.

I look forward to what you guys say. I appreciate all and any advice/feedback and want to know what loads you guys are using for your rifle.

Thanks,

Thanatos-Keres
 
Any 6.5mm diameter bullet will work; Bullets are diameter-specific not cartridge-specific. 130-140 class Bullets are great in the 260R (130 eldm/140 Berger, etc). Since your rifle seems to like the Hornady 130 eldm, I’d start there.
 
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Nice, I'm assuming the heavier the round the more resistance there is to drifting?
Not necessarily. Theres a general correlation between weight and wind resistance but its not absolute. Ballistic Coefficient (BC) is the most commonly used measure for evaluating a bullet’s wind management abilities. BC is a consequence of bullet design, aerodynamics etc. In simple terms, higher the BC the better it will handle the wind.
 
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Unless you’re trying to shoot a mile regularly try the 130-136 bullets all day!
Trust me!!!!



260 is the sperm of Zeus!
6.5CM is the official cartridge of the poofter team shooters.

571D0157-4125-4790-A2EB-655FBF2B3261.jpeg
 
I personally use 140 to 147 grain projectiles. Generally bc covers all aspects related to aerodynamics (encompassing weight and length etc) the higher the bc at similar speeds the less wind drift. You will see these as either G1 or G7 decimal numbers…the higher the more aerodynamic. The numbers are different equations and basically correlate but will be substantially differ say 0.7 G1 and roughly 0.37 G7, G7 tends to be used at longer ranges. But generally you need to balance speed and bc together for your use. 260 is a very good round albeit less popular than 6.5 creed. Be sure to look at reloading manuals to determine load if you are just starting as all components make a difference (you can’t just change case from say Hornady to lapua at max load and assume you are safe).
 
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Jamming also can cause pressure spikes so be careful….jamming is based off case to ogive so it will depend on bullet shape related to length. Jamming is more about bullet making contact with barrel lands not necessarily bullet seated into powder space of the case.
 
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I personally use 140 to 147 grain projectiles. Generally bc covers all aspects related to aerodynamics (encompassing weight and length etc) the higher the bc at similar speeds the less wind drift. You will see these as either G1 or G7 decimal numbers…the higher the more aerodynamic. The numbers are different equations and basically correlate but will be substantially differ say 0.7 G1 and roughly 0.37 G7, G7 tends to be used at longer ranges. But generally you need to balance speed and bc together for your use. 260 is a very good round albeit less popular than 6.5 creed. Be sure to look at reloading manuals to determine load if you are just starting as all components make a difference (you can’t just change case from say Hornady to lapua at max load and assume you are safe).
That's honestly what I'm reading into right now. Makes me wonder why G7 isn't the standard for more modern rounds. I also just read up on something in regards to your example too. Hornady brass runs thinner increasing powder volume compared to the thicker Lapua brass so when loaded to the same max load there will definitely be pressure differences
 
In regards to CBTO/Jam length. I'm concerned about the pressure/compression of a longer bullet in a 260R case seated too deep
Unless you really overcharge the case with powder, you wont have that problem with the 130-140 grain hybrid bullets made by Berger, Sierra and Hornady (as well as other similar bullets).

I'd start 1.0-1.5 grains below book max (Ideally, you should use data from the reloading manual published by the bullet manufacturer but any reputable manual/source will work). and jump them at least .030" to start and adjust seating depth as needed (All the Berger hybrids I've ever worked with perform best at between .030".080" off the lands). Do Not jam these into the lands - they dont like it.

Monitoring for Signs of Pressure
Measure all of your test rounds at the base of the case just above the extractor groove using a 1" micrometer and record the numbers for each charge weight. Then measure the fired cases and compare the before/after numbers. Any expansion more than .0005" indicates you're over-pressure at that charge weight (you may or may not see any signs of pressure on the case head at .0005-.001 expansion but will likely see them beyond that).
 
Jamming also can cause pressure spikes so be careful….jamming is based off case to ogive so it will depend on bullet shape related to length. Jamming is more about bullet making contact with barrel lands not necessarily bullet seated into powder space of the case.
Yeah this is something I will be extremely careful with, I understand that jam/jumping is one of the vital parts of getting the most accuracy out of my rifle
 
Unless you really overcharge the case with powder, you wont have that problem with the 130-140 grain hybrid bullets made by Berger, Sierra and Hornady (as well as other similar bullets).

I'd start 1.0-1.5 grains below book max (Ideally, you should use data from the reloading manual published by the bullet manufacturer but any reputable manual/source will work). and jump them at least .030" to start and adjust seating depth as needed (All the Berger hybrids I've ever worked with perform best at between .030".080" off the lands). Do Not jam these into the lands - they dont like it.

Monitoring for Signs of Pressure
Measure all of your test rounds at the base of the case just above the extractor groove using a 1" micrometer and record the numbers for each charge weight. Then measure the fired cases and compare the before/after numbers. Any expansion more than .0005" indicates you're over-pressure at that charge weight (you may or may not see any signs of pressure on the case head at .0005-.001 expansion but will likely see them beyond that).
Thanks, that really put my mind at ease, and makes me extremely excited to start loading for my rifle. As for monitor for pressure that's where I know I'll have to keep an eye out because I have to clue what to really look for yet, and I would have never thought of measuring anything so I'll definitely be noting that and making it a part of my dev process.
 
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Thanks, that really put my mind at ease, and makes me extremely excited to start loading for my rifle. As for monitor for pressure that's where I know I'll have to keep an eye out because I have to clue what to really look for yet, and I would have never thought of measuring anything so I'll definitely be noting that and making it a part of my dev process.
You're welcome.

Do you have the tools needed to measure shoulder bump and CBTO so that you can set up your sizing and seating dies up correctly?
 
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I have a hornady comparator coming in to measure CBTO to work with my seating die. I'm still trying to wrap my head around shoulder bump though. I don't have anything I can think of to measure that at the moment. I plan on measuring my fired Hornady brass to set my sizing dies around in relation to the shoulder bump and adjust from there? I got the Hornady reloading classic kit and will start from there. I also have my 260R full length custom hornady dies, sizer and seat, and case holder.
 
These are great powders. However, depending on where you are located, we are experiencing fluctuations in temperature and weather. You need to look at temperature stability with powders. I believe RL-17 is going to be less stable.
Thanks for the heads up. I'll be looking around that burn rate for sure. But as a Chicago native i get to experience all for seasons. Sometimes all in one day!... So I'll definitely look for stable powder
 
Thanks for the heads up. I'll be looking around that burn rate for sure. But as a Chicago native i get to experience all for seasons. Sometimes all in one day!... So I'll definitely look for stable powder
H4350 is probably going to be the most stable, with that said, if you want speed RL-17 is your baby. I shoot a bunch of it in several calibers, accuracy is very good and speed normally can't be matched as it's a double base powder. Simply develop your load in the summer and you're good to go. I'm straight east of you so we're in the same situation weather wise.
 
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I have a hornady comparator coming in to measure CBTO to work with my seating die. I'm still trying to wrap my head around shoulder bump though. I don't have anything I can think of to measure that at the moment. I plan on measuring my fired Hornady brass to set my sizing dies around in relation to the shoulder bump and adjust from there? I got the Hornady reloading classic kit and will start from there. I also have my 260R full length custom hornady dies, sizer and seat, and case holder.
You can use a brass case from a .40 S&W cartridge. Knock the primer out and set the mouth of the case on the shoulder of the .260 Rem case.
 
GunBroker will be my go too once my account is verified. But Discord as in the voice chat/video app? Sniper's Hide has a Discord?
Type “discord server reloading” into your browser of choice, results will give you the info you need to join. You have to be quick; sometimes it helps other times it doesn’t.

Also keep an eye on the Reloading and PX subforums as other members will occasionally stat threads informing of stuff in stock. There is a couple running threads like that on here.
 
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I personally use IMR 4350 with Berger 140 Hybrids with either Lapua, Peterson, Alpha or RP Brass, RP Being last choice. I used to run H4350 but its more popular and harder to find so I swapped over for that reason and you can get more speed with less pressure and less powder used with IMR 4350. I have 3 260 Rem's all on Bartlein or Benchmark Barrels 24" 1-8T, I load them around max length for mags 2.850" COAL with Berger 140 Hybrids. 40.5g of IMR 4350 will get you around 2550fps to start and running max compressed loads of 45.5g of IMR 4350 will be around 2925fps never had any pressure signs on any of the 3 setups. I have tested all these at temps from 35 degrees - 90 degrees F and didn't see much difference in speed between the same loads in H4350. If you ever want anymore load info I have about 12yrs of 260 data on hand with both IMR and H4350 and Berger 130 - 140 Hybrids. This is just my $0.02 and like others have said 260 has a wide range of powder you can use that will work very well so if you ask 10 guys you might get 10 different opinions all will most likely shoot lights out.
 
Type “discord server reloading” into your browser of choice, results will give you the info you need to join. You have to be quick; sometimes it helps other times it doesn’t.

Also keep an eye on the Reloading and PX subforums as other members will occasionally stat threads informing of stuff in stock. There is a couple running threads like that on here.
Thanks I really appreciate it. I just joined the server and will keep an eye out here too for everything I will be needing
 
I personally use IMR 4350 with Berger 140 Hybrids with either Lapua, Peterson, Alpha or RP Brass, RP Being last choice. I used to run H4350 but its more popular and harder to find so I swapped over for that reason and you can get more speed with less pressure and less powder used with IMR 4350. I have 3 260 Rem's all on Bartlein or Benchmark Barrels 24" 1-8T, I load them around max length for mags 2.850" COAL with Berger 140 Hybrids. 40.5g of IMR 4350 will get you around 2550fps to start and running max compressed loads of 45.5g of IMR 4350 will be around 2925fps never had any pressure signs on any of the 3 setups. I have tested all these at temps from 35 degrees - 90 degrees F and didn't see much difference in speed between the same loads in H4350. If you ever want anymore load info I have about 12yrs of 260 data on hand with both IMR and H4350 and Berger 130 - 140 Hybrids. This is just my $0.02 and like others have said 260 has a wide range of powder you can use that will work very well so if you ask 10 guys you might get 10 different opinions all will most likely shoot lights out.
Good info. A friend basically shoots the same load.
 
I personally use IMR 4350 with Berger 140 Hybrids with either Lapua, Peterson, Alpha or RP Brass, RP Being last choice. I used to run H4350 but its more popular and harder to find so I swapped over for that reason and you can get more speed with less pressure and less powder used with IMR 4350. I have 3 260 Rem's all on Bartlein or Benchmark Barrels 24" 1-8T, I load them around max length for mags 2.850" COAL with Berger 140 Hybrids. 40.5g of IMR 4350 will get you around 2550fps to start and running max compressed loads of 45.5g of IMR 4350 will be around 2925fps never had any pressure signs on any of the 3 setups. I have tested all these at temps from 35 degrees - 90 degrees F and didn't see much difference in speed between the same loads in H4350. If you ever want anymore load info I have about 12yrs of 260 data on hand with both IMR and H4350 and Berger 130 - 140 Hybrids. This is just my $0.02 and like others have said 260 has a wide range of powder you can use that will work very well so if you ask 10 guys you might get 10 different opinions all will most likely shoot lights out.
Great insight, I experience those temps throughout the year so I'll look into IMR. I'm eager to get things going so if I can find some in stock I'll snag some. Any suggestions on primers? I'll be starting my loads with once fired Hornady Brass and I don't know how to approach what kind of primers to get.