Blocked bolt with reloaded ammo

[Praire Dog]

Start high and go low.....?????????????????

No hehehe I will try around 43.5 (maybe 43.3, 43.4, 43.5, 43.6 and 43.7) because I had already tried loads from 42 to 45 increasin 0.3 grains. And my best groups (except with 44.8) were with 43.5 gr.

That's why I will try around 43.5 and I will use this load unless I will have excesive pressure.

 

[CVCOBRA1]

But didn't you already have problems with bolt lift on any of those reloads?
You sure you not looking at RX powder and not RS powder?

Alliant Reloader powder can be listed or named three different ways:
Reloader 22=RE-22 or Re22, RL-22, RX22
http://www.exteriorballistics.com/reloadbasics/burnrates.cfm
Not sure if Alliant Reloader 50 was ever listed as RX50 but anything is possible

 

[Praire Dog]

But didn't you already have problems with bolt lift on any of those reloads?
You sure you not looking at RX powder and not RS powder?

Alliant Reloader powder can be listed or named three different ways:
Reloader 22=RE-22 or Re22, RL-22, RX22
http://www.exteriorballistics.com/reloadbasics/burnrates.cfm
Not sure if Alliant Reloader 50 was ever listed as RX50 but anything is possible

I am sure it is RS50, and my data too, I found it in the manufacturer's website.

I didn't have problems with the bolt all the time, in my first loads I didn't have problem. I can't remember when this problem started, but I think 43.5 was ok. As I said, I'm new on this, and I didn't know that was a sign of pressure. If when I shoot 43.5 (it is 1.3 grains less than now) one more time is has the same problem I will drastically reduce the load.

 

[Praire Dog]

If it's helpful for someone, I contacted with the manufacturer and they told me they didn't have experimental results for this bullet. So they sent me the following results that they got from ballistic software.

My load is apparently correct, unless the volume is less than that. I have to measure it. But anyways, my rifle doesn't want it, so I will reduce the load and we will see what happens.

Thank you very much for your help guys!

 

[hangfire]

I ran your load through Quickload software and even allowing only 55gr case capacity you should be about 500 bar below PMax. The pics you posted show a nice radius on the primer so I'd say pressure was OK. I'd have the chamber checked for dirt and pitting

 

[Praire Dog]

Hi all

I have been checking today some rounds and the problem of the blocked bolt starts with loads of 42.8 gr and higher.

Some guys on the range told me that they use the same bullet with 45 gr of powder and even more. They told me that my OAL of 2.8 is too short and it produces many pressure in my rifle, and they recommended me to go to 2.82 or 2.84

Do you think it is safe to try my 44.7gr loads with a OAL of 2.82? Or should I forget about OAL and use only loads under 42.8 with 2.8 OAL?

 

[Dean2]

Hi all

I have been checking today some rounds and the problem of the blocked bolt starts with loads of 42.8 gr and higher.

Some guys on the range told me that they use the same bullet with 45 gr of powder and even more. They told me that my OAL of 2.8 is too short and it produces many pressure in my rifle, and they recommended me to go to 2.82 or 2.84


Do you think it is safe to try my 44.7gr loads with a OAL of 2.82? Or should I forget about OAL and use only loads under 42.8 with 2.8 OAL?

Four thou is not going to make that big a diff on pressure. To prove it load 42.7 and seat to 2.84. My bet is u will see the same pressure issues u do at the shorter COAL

If u are still using PPU brass a max load of 42.7 is reasonable. It is common for military and ppu to hit max 5% _ 8% below Rem brass. On 45 grains that would be 2.25 to 3.6 grains. If you started using brass with more capacity pressure issues at that light a load tells me u REALLY need to get this gun looked at by a good gunsmith.

Like I and others suggested before chrono the friggin load. my bet is u are already at max vel. If u are at max vel or not quit trying to add more powder to a load u already know is over pressure. Concentrate on finding an accurate load below 42.7 grains.

 

[Gord0]

I was making some mixed brass plinking loads for my .224 / 5.56's. Middle of the road load of H335 and a 55gr. Ended up with a case stuck in the chamber from being over pressure. It was a PPU.

 

[Praire Dog]

Yes, I was still using PPU brass. So I think I will start with 40 gr and I will try new loads until 42 gr. Between 42 and 42.7 I couldn't find good groups.

I don't have a chronographer yet, but I will buy it soon. But while I don't have it, do you think 40 gr is a good starting load? Or could I start with less than that?

 

[Dean2]

Yes, I was still using PPU brass. So I think I will start with 40 gr and I will try new loads until 42 gr. Between 42 and 42.7 I couldn't find good groups.

I don't have a chronographer yet, but I will buy it soon. But while I don't have it, do you think 40 gr is a good starting load? Or could I start with less than that?

I would start at 39 and work up .2 at a time. I would also start at the max coal that will fit comfortably in the mag. When I found the first load that would hold an inch I would then play with the COAL by going .005 shorter each time at the same charge weight to see if I could find one that shrank the group without going shorter than 2.82. once I established the best COAL I WOULD THEN KEEP GOING UP , ignore caps I left the lock on, .2 grains to a max of 42.7 or to where pressure starts showing up again. This way you get max vel and max accurracy. COAL will often impact group size more than charge wieght in many guns.

 

[hangfire]

Pressure is dictated by a number of factors, charge weight, internal case capacity, overall length of cartridge, bullet weight and bore dimensions, a change in any one of these will effect pressure. PPU brass as people have said tends to have a lower internal capacity then most other brands. As has been mentioned before the relationship of the bullet ogive to the rifle lands has more effect on accuracy then charge weight. When I'm developing a load I find the lands, load 3 rounds to that dimension then three rounds 10 thou shorter and carry on till 70 thou off the lands. I choose a load that will be under pressure at the shortest dimension. presuming I obtain an acceptable group from one of these loads I will then play with powder charges. I have sometimes had to load 120 thou of the lands to get a decent group. I once owned two Rem 700's in .308 and using the same batch of brass, powder and the same bullets had a difference of 1 grain of powder in max pressure between the two rifles

 

[Praire Dog]

Is there a reason to go from the lands to a shorter OAL? Why not the opposite, to start in the SAAMI OAL and increase the lenght?

In fact the 50% o my groups are already under 1 inch betrween 42 and 42.7 gr, but when I tried my old loads with 44.7 and 44.8 I got less than 0.3 MOA. I hope I will find such groups under 42 gr.

 

[hangfire]

Is there a reason to go from the lands to a shorter OAL? Why not the opposite, to start in the SAAMI OAL and increase the lenght?

In fact the 50% o my groups are already under 1 inch betrween 42 and 42.7 gr, but when I tried my old loads with 44.7 and 44.8 I got less than 0.3 MOA. I hope I will find such groups under 42 gr.

I'm not sure why it became accepted practice to start at the lands. Probably because 1. it is an ideal reference point and 2. back in the day people always used to say you have to load to the lands to be accurate. The second is untrue today, it may have been correct when mass production engineering was far less precise then it is today.

When you say your old loads did you use a different make of case or overall length when you first used them

 

[Praire Dog]

I only wanted to thank you all. Your advices were very helpful. I have already found a good load, 39.0 gr There is not overpressure, the bolt opens easily and the precision is very good.