Ullr PrecisionReading a pellet tin: calibre, count, lot code and date
A pellet tin carries more useful information than most shooters notice. Here's what the marks usually mean, and why a careful shooter writes some of them down.
Calibre: ".177" and "4.5 mm"
Calibre is the nominal size of the bore the pellet is made for. .177 is the size in inches, and 4.5 mm is the metric name for the same calibre. You'll often see both on one tin.
Calibre is a name, not a precise measurement of each pellet. Some makers also print a head size in millimetres, to two decimal places, so shooters can choose the size that suits their barrel. Ullr Precision tins will show the head size as well as the calibre.
Pellet type
Tins often name the general type of pellet. "Diabolo" is the classic waisted airgun pellet shape, and the word is a generic type name, not a brand. Other type names you may see describe the shape of the front of the pellet.
Weight
Many tins give a weight per pellet, usually in grains (gr), sometimes in grams as well. It's a nominal figure for the batch.
Count
The count is how many pellets the tin should hold, such as 500. A count is something you can check. If you want to know, count them (or weigh the tin and compare with an empty one).
Lot code and packing date
A lot code (sometimes "batch" or "LOT") identifies which production run the pellets came from. A date may show when the tin was packed.
Why this matters:
- Pellets from one lot were made and packed together. Pellets from different lots may differ slightly.
- If you find a tin that suits you, the lot code lets you note exactly which batch it was.
- If there's ever a problem with a batch, the lot code is how it's traced.
Tip: write the lot code in your shooting notes with every group. Our Proof Card target has a space for it. If you mix pellets from two tins, note both codes, or better, don't mix them.
Producer name and address
A tin should tell you who is responsible for the product and how to contact them. In GB this is part of general product safety rules: the producer's identity and details, and a batch reference where appropriate. It's there for traceability, so a problem can be reported to the right people.
Warnings and age
Tins commonly carry warnings such as "Contains lead", "Wash hands after handling" and "Keep out of reach of children", and an age notice. Read them. They're short for a reason.
Look after the tin
Keep pellets in their tin, with the lid on. The tin protects the pellets from knocks and damp, and it keeps the lot code, count and warnings with them. Once pellets are tipped into an unmarked pot, that information is gone.
What will be on an Ullr Precision tin
AeroFlare™ tins will carry the calibre, head size, pellet type, count, a lot code, a date, the producer details and warnings.
Quick checklist
- Calibre and head size: does it match what you use?
- Count and weight: note them.
- Lot code and date: copy them into your notes.
- Producer details: there if you need to report a problem.
- Warnings: read them.
Ullr Precision · Measured, not claimed.
Sources
- .177 = 4.5 mm generic calibre naming (as printed on pellet tins)
- General Product Safety Regulations 2005 (GB), reg. 7(4)(a): https://www.legislation.gov.uk/uksi/2005/1803/regulation/7 (checked 05/11/2026)